“Improving the balance, coordination, and inclusiveness of development” is an inevitable requirement for regional development in China. The Yangtze River Economic Belt is a resource belt, industrial belt, urban belt and a leading demonstration belt for ecological civilization construction with the most comprehensive advantages and development potential in China. Promoting the coordinated and balanced development of the Yangtze River Economic Belt is one of the important ways for China to achieve common prosperity. Based on the evaluation index system of the coordinated and balanced development index, this paper uses a variety of quantitative analysis methods to reveal the current situation of the coordinated and balanced development in the Yangtze River Economic Belt. The results are as follows: (1) Coordinated and balanced development is a theoretical innovation in the practice of regional development, which aims to improve the coordination, balance and integration of regional development in China, thereby upgrading the allocation efficiency of regional elements. (2) At the inter-provincial level, the overall status of the coordinated and balanced development of the Yangtze River Economic Belt is not ideal, and the problems of unbalanced and uncoordinated in the development process are relatively prominent. (3) At the prefecture level, there are huge differences among 110 cities, and the sub- indices generally show a decreasing trend from the lower reaches to the upper reaches. (4) In order to further promote the coordinated and balanced development of the Yangtze River Economic Belt in the future, the region needs to pay more attention to cross-regional coordination and cooperation, take common prosperity as the fundamental foothold, accelerate the construction of new urbanization, focus on building a comprehensive stereoscopic transportation corridor across the river basin, and continue to improve ecosystem of the Yangtze River basin.

Based on the data of biomedical industry cooperation patent applications in the Yangtze River Delta region from 2001 to 2018, using social network analysis methods to explore the spatial structure of the innovation network between cities in the Yangtze River Delta region, and using the panel negative binomial fixed effect model to analyze the influence mechanism of the network structure. The research found that: the biomedical industry innovation network in Yangtze River Delta presents a simple to complex, low-level to high-level evolution process; a radial structure with Shanghai as the center is presented in geographic space, and the density of the innovation network is high in the east and low in the west. Innovation nodes and innovations Contacts are mainly concentrated on the east side of the Yangtze River Delta. The construction of the biomedical industry innovation network between cities in the Yangtze River Delta is not only affected by its own economic development level, industrial structure, foreign investment and geographic proximity, but also by the density of the innovation network within the city, and the status of cities in the national biomedical industry innovation network will also have a positive effect on the construction of innovation cooperation between cities in the region. At the end of the paper, in view of the practical problems existing in the development of biomedical innovation in the Yangtze River Delta, such as the core-edge structure, the lack of cross-regional cooperation and homogeneous competition, this paper puts forward targeted policy suggestions.

Based on the panel data of high-tech manufacturing industry in 30 provinces of China from 2011 to 2019, this study uses the Output-oriented Directional distance function and the β convergence panel model of bi-directional fixed effect to measure the environmental efficiency of 30 provinces under the framework of Porter Hypothesis, and studies the convergence of the environmental efficiency of high-tech manufacturing industry in the Yangtze River Economic Belt. Some results show that: the intensity of environmental regulation in the Yangtze River Economic Belt has an “inverted U-shaped” trend, and the environmental efficiency in the upper, middle and lower reaches of the Yangtze River Economic Belt is increasing step by step. Environmental efficiency has a significant ?? convergence, and environmental regulation can drive the growth and convergence of environmental efficiency after short-term accumulation. There exists a virtuous cycle of “environmental regulation—increased investment in innovation—reduced economic benefit—emerging innovation benefit—improved environmental efficiency” in the high-tech manufacturing industry of the Yangtze River Economic Belt. In order to further improve the environmental efficiency of high-tech manufacturing industries in the Yangtze River Economic Belt, it is necessary to design reasonable environmental regulation intensity and appropriate environmental regulation policies according to local conditions, gradually improve the intensity of environmental regulation, and strengthen the “innovation compensation effect” of high-tech manufacturing enterprises.

Grasping the spatial relationship of human settlement environment and its driving factors is of great significance for the promotion of sustainable development of human settlement environment. On the basis of introducing the modified gravity model to construct the spatial network correlation of human settlement environment of urban agglomerations in the middle reaches of the Yangtze River, this paper uses the social network analysis method to explore the spatial network structure and its influencing factors of human settlement environment of urban agglomerations in the middle reaches of the Yangtze River. The results show that: （1）During the research period, the spatial network intensity of human settlement environment of urban agglomerations in the middle reaches of the Yangtze River has become increasingly close, and a relatively stable network of human settlement environment has been formed, but its network correlation is still relatively loose, and the network structure needs to be further optimized. （2)Wuhan, Changsha, Nanchang and other relatively developed provincial capitals are in the core leading position of the spatial correlation network of human settlement environment, which has a significant impact on the spatial correlation of human settlement environment; while Xiaogan, Shangrao, Ji'an, Fuzhou and other remote areas are in the absolute edge of the network, which has a weak impact on its spatial correlation. （3)The human settlement environment network of urban agglomerations in the middle reaches of the Yangtze River is mainly based on the transmission and spillover effects among the plates, while the spillover effects within the plates are relatively less. Among them, five cities such as Wuhan, Nanchang and Yichang belong to the “net benefit plate” and play a “leading” role in the network; seven cities such as Xiaogan, Huangshi and Huanggang belong to the “bidirectional spillover plate”; six cities such as Yingtan, Pingxiang and Xinyu belong to the “agent plate” and play a “bridge” role in the network; ten cities such as Jiujiang, Xianning and Yueyang belong to the “net spillover plate”. (4）The city distance, the economic development level difference, the industrial structure difference and the urbanization level difference have significant negative effects on the spatial correlation intensity of human settlement environment. The total population difference and the per capita financial expenditure difference have significant positive effects on them, while the regression coefficient of the openness difference is positive but not significant, its response mechanism and effects need to be improved and enhanced.

Quickly and accurately identifying the spatial distribution and evolution of heat sources in industrial enterprises can help reveal the changing laws of industrial geographic locations and pollution sources, and is of great significance to industrial layout adjustment, green development, and environmental pollution supervision. Considering that the Yangtze River Delta region of Jiangsu is an important industrial zone in the Yangtze River Delta and an important industrial belt in the Yangtze River Economic Belt, this paper uses the unique properties of industrial thermal anomalies in space and time, and combines the 2012-2020 NPP-VIIRS satellite long-term sequence segment. Using the fixed threshold method to identify and extract thermal anomalous points, the location distribution and changing laws of industrial heat source thermal anomalies in the Jiangsu area along the river were studied to reveal the temporal and spatial pattern of the development of industrial enterprises in the area along the Jiangsu River. Main conclusions: (1) By using the thermal anomaly point data of the NPP satellite VIIRS sensor, the location identification and spatial evolution analysis of industrial heat sources along the Yangtze River in Jiangsu from 2012 to 2020 were carried out. The number of industrial thermal anomalies generally shows a trend of first decreasing and then increasing. In 2020, there will be a sharp decrease, and at the same time, there will be a distribution pattern of “more in the south and less in the north”. (2) From 2012 to 2020, the FRP of the radiation intensity of industrial thermal anomalies generally showed a “U”-shaped change trend, and suddenly decreased sharply in 2020. Among them, the FRP values of Nanjing, Changzhou and Suzhou have been in the top three and all are greater than 1 000 MW, which is consistent with the trend of changes in the output statistics of industrial enterprises along the Yangtze River in Jiangsu. (3) In 2012, 2016 and 2019, the high-density nuclei of industrial thermal anomalies were mainly distributed along the Yangtze River, and the number and location were relatively stable. The overall density core points show a trend of shifting from upstream to downstream, of which Yangzhou and Nantong are the two representative cities with significant changes.

Urban vitality is the guarantee for urban sustainable development. This study quantitatively evaluated the vitality of Changzhou from two aspects of vitality representation and vitality composition by using methods such as entropy method, space syntax and bivariate spatial autocorrelation analysis and data on population grid, points of interest and nighttime light. Then, the spatial distribution pattern of urban vitality and the spatial correlation between vitality representation and vitality composition were analyzed. The results showed that the vitality of Changzhou presents the single-center feature of ‘high in the center and low in the surroundings’ and extends outward along the planning development axis. In general, the blocks’ POI density and local accessibility show significant positive correlation with vitality representation, while the global accessibility shows negative correlation with vitality representation. Improving the blocks’ local accessibility and functional facilities density is beneficial for attracting human activities and promoting urban vitality, but improving the blocks’ global accessibility by constructing regional roads may lead to the decline of vitality. In addition it can also be found that there is a partial mismatch between human activities and space function. On the one hand, some urban villages and old community with high intensity of human activities show insufficient function configuration. On the other hand, the small commercial, industrial and residential activity centers outside the inner ring have a high density of functional facilities but their service population and service scope are limited. In conclusion, this study reveals the spatial distribution and correlation characteristics of urban vitality in Changzhou city, and identifies the mismatch between human and space, which can provide reference for urban vitality construction, resource allocation and urban management.

In China, population shrinkage has become a major issue and challenge during the process of regional high-quality development and new urbanization. Based on the Hubei Province population-related data from 2000 to 2015, this paper focuses on the spatial change characteristics of population shrinkage in 91 county-level administrative units to cross-analyzs the evolution pattern in the economic and spatial dimensions of each county during the process of population change, and studies the impact mechanism of population shrinkage with geographically and temporally weighted regression（GTWR）model. The study draws the following conclusions: (1) From 2000 to 2015, a total of 57  counties (cities and districts）  in Hubei Province experienced population shrinkage, of which 6  counties (cities and districts)  experienced urban population shrinkage, and 72  counties (cities and districts)  experienced rural population shrinkage.Since 2006, the total population and urban shrinkage in Hubei Province have decreased, forming a pattern of long-term urban population growth and rural population shrinking. (2) From the perspective of economic and spatial dimensions, urbanization and Return migration have improved the overall economic level and economic density. However, the economic hot spots have not formed a proliferation effect on its surrounding areas. In some areas, the unreasonable construction land planning caused space shrinkage in the early stage,and tends to be intensive and rational in the later stage. (3)The impact degree of influencing factors, industrial structure>government investment>population structure>market size, various factors form different influence in different regions.Finally,several strategies for coping with population shrinkage are proposed such as coordinate regional strategic layout,optimization and upgrading of industrial structure,promotion of human-centered urbanization, improvement of regional development quality and optimization of fiscal expenditure structure.

 The purpose of this paper is to calculate the “consumption-output” ecological footprint account according to the “national hectare” equilibrium factor and yield factor, and to study the ecological sustainable status of cultivated land in the Yangtze River Economic Belt based on the improved ecological sustainability index and ecological pressure index. The results are shown as follows: (1) The equilibrium factor factor and yield factor of “national hectare” show a trend of fluctuation and decrease, with obvious temporal sequence and regional difference. (2) The demand, supply and output of cultivated land in major grain-producing areas are relatively high, while those in economically developed areas in the lower reaches or less developed areas in the upper reaches are on the contrary. (3) All provinces in the Yangtze River Economic Belt give full play to their comparative advantages in agricultural development depending on the resource endowment and function orientation, and the degree of ecological sustainability continues to improve,in addition to Shanghai and Zhejiang.However, the cultivated land is in the state of overloading and utilization, leading to the great ecological pressure. In conclusion, the sustainable development of cultivated land needs to pay attention to the sustainable illusion caused by the increase of production, and prevent the phenomenon of cultivated land quality decline and ecological degradation caused by excessive development and utilization intensity.

In order to analyze the transmission characteristics of nitrogen, phosphorus and silicon in the middle and lower reaches of the Yangtze river and the contribution of the Dongting Lake, Han River and Poyang Lake to the main stream, water samples were collected from the front of the Three Gorges dam to the estuary along the main stream and the entrances to the Yangtze River of the Dongting Lake, Han River and Poyang Lake in September 2020. Concentrations of nitrogen, phosphorus, silicon were measured, the variation trend of nutrient along the river was analyzed, nutrient flux and contribution of main tributaries were calculated. The results show that the total nitrogen concentration in the middle and lower reaches of the Yangtze River decreases along the river and fluctuates between 1.23 mg/L and 2.32 mg/L, and the proportion of dissolved nitrogen is more than 95%. The concentration of total phosphorus increases along the course and fluctuates between 0.01-0.08 mg/L, mainly in granular form. The dissolved silicon concentration increases sharply at the Hankou section, and the mean value from the front of the Three Gorges Dam to Hankou section is 5.52 mg/L, and the mean value from the Hankou section to estuary is 10.8 mg/L. Fluxes of total nitrogen, total phosphorus and dissolved silicon all increase obviously along the river. The tributary river and lakes contributes a lot to the transport of nutrients in the main stream, among which Dongting Lake contributed the most, contributing 163.2%, 67.9% and 23.6% to the transport fluxes of total nitrogen, total phosphorus and dissolved silicon respectively, but the water quality of the main stream does not change obviously after Dongting Lake enters. The comprehensive trophic level index fluctuates between -12.72% and 7.85% after the Dongting Lake, Han River and Poyang Lake merge into the main stream. This study is helpful to understand the nutrient status of the middle and lower reaches of the Yangtze River and the contribution of the tributary river and lakes to the main stream, and to provide scientific basis for water environmental management in the middle and lower reaches of the Yangtze River.

Afforestation project on sides of the Yangtze River focuses on solving the problems of broken green belts on both sides of the river and the fragile ecological functions of forests, so as to build a continuous, complete and stable forest ecosystem along the Yangtze River. Based on the morphological spatial pattern analysis (MSPA), this paper identified the forest ecological pattern before and after the implementation of the project in Shishou City, screened the forest ecological sources, constructed resistance surfaces by combining the landscape types, human activity intensity and other factors, extracted the forest ecological corridors, graded the importance, and constructed the forest ecological network. The results show that the forest resources in Shishou City are relatively rich, the landscape patches are large and fragmented, which makes it difficult to exchange material and energy with other surrounding landscapes. There is no absolute positive correlation between landscape patches area and the importance of connectivity. The afforestation project on sides of the Yangtze River had promoted the closure of the afforestation fault belt along the Yangtze River and its tributaries, increased the patch area of forest landscape resources, reduced the complexity of the edge, alleviated the fragmentation degree of patches, strengthened the connectivity between forest landscape patches, and was conducive to species migration and gene exchange. After the implementation of the project, the distribution of ecological corridors in the source area was not uniform. Through the ecological network planning, the connection level of forest ecological patches in the study area is significantly improved, and the effectiveness and stability of forest network connection are increased. The rational planning of ecological network can connect forest resources, and the combination of farmland and forest network can form a complex ecological network pattern of mountains, rivers, forests, fields and lakes with stable structure and perfect function.

The balance of supplies and demands of ecosystem services (ESs) is of great significance to regional sustainable development. At present, the analysis of the driving forces of supplies and demands for ESs in regions with high spatial heterogeneity needs to be further deepened. In this study, 6 ESs including water yield, grain yield, carbon sequestration, water retention, soil conservation and recreation services in Sichuan Province were calculated. Meanwhile, the surplus, deficiency and their spatial aggregation patterns of the 6 ESs were also analyzed. Finally, in order to provide the evidences for partitioning management in Sichuan Province, the key driving forces of supplies and demands of ESs at provincial and ecoregional scales were carried respectively by using RDA. The results showed that: （1) All the 6 ESs were in surplus generally; （2) The distributions of supplies and demands of 6 ESs, the state of surplus and deficits as well as the spatial aggregation pattern revealed obvious spatial heterogeneity, which were highly correlated with ecoregions; （3) Precipitation, cultivated land, slope and gross domestic product were important driving forces leading to the highly spatial heterogeneity of supplies and demands of ESs in Sichuan Province. However, scale effects of the impacts of different driving forces on ESs were observed between provincial and ecoregional scales. Besides, obvious differences in the types, orders and directions of the main driving forces of ESs can be observed at different ecoregions, which indicated that it is necessary to explore the driving forces of supplies and demands of ESs at the different regions in Sichuan Province or other areas with high spatial heterogeneity. 

The mid summer and autumn droughts refers to droughts that occur in summer or autumn, which occur frequently in Chongqing and cause economic losses. Based on daily precipitation data of 34 national meteorological stations from July to September during 1965-2016 in Chongqing, the temporal and spatial variation of the mid summer and autumn droughts were analyzed by Standardized Precipitation Index (SPI) and precipitation anomaly percentage index (PA). By Spearman rank correlation method and stepwise regression method, factors with strong correlation were screened out from climate factors. The results showed that the frequency of continuous mid-summer and autumm droughts from July to September was 7.7%. The drought synchronization accounted for 15.4% in July-August and 13.5% in August-September. The drougnts varies greatly in Chongqing from 1960s to 1970s, the mid summer and autumn droughts was getting more serious; since the middle and late 1980s, droughts and floods have appeared alternately; in the 21st century, severe summer and autumn droughts occurred frequently. After the 1960s, the annual average total number of drought xun (ten-days) increased from 3.3 to 4.1 xun, and the number of coutinuous drought xun increased from 2 to 2.5 xun. From 1965 to 2016, the annual average total number of drought xun in the western region was 3.6 xun, and the number of coutinuous drought xun was 2.2 xun, which was relatively small. After 2006, the mid summer and autumn drought was mild in the southeastern and northeastern regions, and severe in the middle and the western regions. The mid summer and autumn droughts in Chongqing are closely related to the circulation and SST anomalies. The main correlated factors include Northern Hemisphere subtropical high ridge position index, Northern Hemisphere subtropical high northern boundary position index, the NINO A SSTA index and the Kuroshio current SST index. The SPI of Chongqing in July was negatively correlated with the Northern Hemisphere subtropical high ridge position index in January of the same year; the SPI in September was negatively correlated with the NINO A SSTA in April of the same year. The research results can provide a theoretical basis for ensuring water security and realizing the scientific allocation of water resources in Chongqing.

The Yangtze River Economic Belt is one of the areas with the sharpest human-land conflict in China. In recent years, the rapid development of the Yangtze River Economic Belt has caused a great negative impact on regional ecosystem services. It is of great significance to realize the sustainable development of the region to deeply understand the spatio-temporal evolution process and coupling coordination between ecosystem services and economic-social development. Based on the analysis of the spatio-temporal pattern of economic-social development and ecosystem service value in the Yangtze River Economic Belt, the study analyzed the spatio-temporal evolution characteristics of the coupling coordination between them. The results show that: (1) From 1995 to 2015, the level of economic-social development in the Yangtze River Economic Belt showed a significant upward trend, and the ecosystem service value declined significantly after 2005, which was consistent with the acceleration period of economic-social development. At the same time, the coupling coordination degree between economic-social development and ecosystem service value in the Yangtze River Economic Belt shows an overall upward trend, and there are significant spatial differences in the coupling coordination degree among provinces. (2) Chongqing, Jiangsu, Anhui and Sichuan experienced rapid economic-social development during the study period, but ecosystem protection lagged behind the economic-social development, which made them from the backward areas of economic-social development to the backward areas of ecosystem services at the end of the study. It shows that these provinces have damaged the capacity of natural ecosystem to some extent with the rapid economic-social development. The economically developed provinces in the middle and downstream of the Yangtze River Economic Belt are faced with the problem of how to coordinate the relationship between social development and ecological protection, while the economically less developed provinces in the upstream of the Yangtze River Economic Belt are faced with the dual pressure of improving the level of economic-social development and ecological protection.

Due to the regional resource endowment differences along the Yangtze River, uneven distribution of industries, large income gap and so on. This leads to the differences in the path, space, time and degree of different pollutants in the production process of different regions along the Yangtze River. Then, regional differences will occur when exploring the linkage between the economy and environment along the river, so there are various forms of EKC in different regions. Based on the panel data of 45 cities along the Yangtze River from 2003 to 2018, this paper selects five single environmental indexes from the five environmental levels (atmosphere, water, sound, soil and biology), and constructs a comprehensive environmental index. The traditional EKC and SDM models are set according to the characteristics of environmental indicators .Relying on the comparison of single and comprehensive environmental index EKC curve, this paper classifies the cities along the river by defining the scope of the basin and dividing the level of economic development, and studies the internal linkage between economic growth and environmental quality. The results show that: (1) There are limitation and instability in measuring environmental quality by single environmental index. When the per capita industrial sulfur dioxide emission, per capita industrial waste water emission and urban road noise are taken as the environmental quality indicators, the economic growth and environmental quality present a "U" curve. However, when comprehensive environmental indicators are used, they are inverted "U" type. At the same time, each index shows different degrees of spatial spillover effect, and the most significant spillover effect is industrial wastewater. (2) The environmental governance of cities along the Yangtze River lacks the overall situation, and the scope of governance needs to be expanded. In recent years, the emission reduction effect of industrial sulfur dioxide and industrial wastewater is remarkable, but the green coverage rate of the built-up area and the comprehensive utilization rate of industrial solid waste show a slow downward trend at this stage. (3) Due to the heterogeneity of samples, the linkage relationship between comprehensive environmental indicators and economy presents a variety of forms: the upstream area is inverted “U” type; the middle and high-income area is positive “U” type; the downstream area is “W” type; low-income areas are of the “M” type. It is found that the environmental problems in the downstream areas are more prominent and need to be rectified, and the low-income areas should take preventive measures, take active measures and control ahead of time.

The performance evaluation system for the water ecological function zoning management of Taihu Basin has not been established yet. Therefore, we can hardly give an accurate evaluation of the zoning management system implementation status and the key impact factors that affect the ecosystem health of Taihu Basin. Based on the "pressure-state-response" model, we constructed the performance evaluation index system with different spatial and temporal scales and management boundaries. Differentiated performance evaluation was then conducted under different management objectives of water eco-environmental functional zoning in Taihu Basin.

Lake chief system is an important institutional innovation in the process of water environment governance in China. It is of great practical significance to solve the problem of water pollution control and realize the sustainable utilization of lake water resources by establishing and perfecting the responsibility system of Party and government leadership as the core and implementing the responsibility of territorial management. Used the data of Wuhan Environmental Status Bulletin and Wuhan statistical yearbook from 2007 to 2017, this paper discusses the impact of Lake length system on water environment governance effect and its mechanism, and carries out a series of robustness tests on this basis. The results showed that: （1）The lake chief system significantly improves the comprehensive water quality and the total value of pollutants exceeding the standard in the pilot lakes. The above conclusion is still valid after a series of robustness tests.（2）Mechanism analysis shows that, on the one hand, the lake chief system improves the effect of water environment governance by promoting investment in environmental governance and reducing industrial sewage discharge.（3）The heterogeneity analysis shows that the lake chief system can significantly improve the water environment governance effect of the high economic level jurisdiction. Compared with the inter regional lakes, the lake chief system significantly improved the effect of non trans regional lake water environment governance. The research results provide decision-making reference for improving the lake chief system, forming a normalized and systematic water resources management system, and promoting the modernization of water environment governance system and governance capacity.

Green development efficiency is an important reference to evaluate the quality of green development. Based on the static and dynamic perspectives respectively, this paper measures the green development efficiency of Chengdu-Chongqing Twin City Economic Circle from 2007 to 2019 using super efficiency SBM model and Malmquist index，analyzes its temporal and spatial evolution characteristics and influencing factors，and predicts its green development efficiency for the 14th Five-Year Plan period using Winter linear and seasonal exponential smoothing method. The results show that:(1)The green development efficiency of Chengdu-Chongqing Twin City Economic Circle is a higher level of 0.882，and it presents the time sequence characteristics of the transformation from“higher level and larger gap”to“higher level and smaller gap”，but it is still lower than the average level of Yangtze River Delta Urban Agglomerations;The average value of Malmquist is 1.278, indicating a high growth of the green development efficiency, and the overall growth is faster than the Yangtze River Delta Urban Agglomerations;（2）The Chengdu-Chongqing Twin City Economic Circle has gradually formed a distribution pattern with“Ya'an Ziyang Chongqing”and“Chengdu Suining Guang'an”as double parallel principal axis areas with a high efficiency green development,and“Yibin Luzhou”and“Mianyang Dazhou”as two wings with a low efficiency green development;（3）For the improvement of green development efficiency of the Chengdu-Chongqing Twin City Economic Circle, the contribution rate of technological progress > the contribution rate of technical efficiency > the contribution rate of scale efficiency, and according to this, it can be divided into comprehensive promotion development type, special leading development type and single hindering development type.

The urban green development level measurement system is established，and Jiangxi urban green development level during the period of 2011-2018 is dynamically measured and its spatial and temporal evolution characteristics are analyzed based on “vertical and horizontal” pull-off method，exploratory spatial data analysis method，convergence analysis method and so on. The complex multi-factors that influence the green development of urban is taken as a research perspective，and the network topology Tobit model of Jiangxi urban green development level covering environmental regulation，technological innovation，governance transformation，external openness，human capital and industrial agglomeration is constructed. Results show that，firstly，the overall green development level of the urban in Jiangxi has steadily increased. The resource environment and the economy development are respectively the dominant guarantee and the key weakness of the green development level of the urban in Jiangxi. The green development level of the urban in the Great Nanchang Metropolitan Area has relatively significant feature of descending gradient distribution. Secondly，the urban green development level had spatial negative correlation，which has been decreased. Nanchang has been significantly becoming a hot-spot. Jiangxi urban green development level has significant trend of absolute convergence in the long term. Thirdly，the environmental regulation，technological innovation，transformation of governance，openness to the outside world，human capital and industrial agglomeration degree have shown different significant impacts on the green development level of the urban in Jiangxi. The Porter Hypothesis is verified.

Because of complex underlying surface, low surface wind and high air humidity, which are easy to cause the accumulation of PM_2.5 in main urban area of Chongqing, Precipitation play an important role in PM_2.5 removal by the scavenging effect. Based on the meteorological observation data at Shapingba station and the hourly PM_2.5 mass concentration observation data in main urban area of Chongqing from 2015-2020, the scavenging effect of different type of rainfall processes on PM_2.5 mass concentration is analyzed. The results showed that: In the threshold analysis of PM_2.5 mass concentration in different rainfall processes, the initial mass concentration is the main influencing factor. Both rainfall processes with cold front and strong rainfall with no（weak）cold air can effectively reduce PM_2.5 mass concentration. In weak rainfall processes with no（weak）cold air, rainfall erosion and the hygroscopic growth of PM_2.5 make the PM_2.5 mass concentration change smaller. Cold front rainfall process average scavenging rate is higher than rainfall process with no（weak）cold air 1-2 grades, The average scavenging rate of rainfall process with no（weak）cold air increases with the increase of hourly maximum rainfall intensity, rainfall duration and accumulated rainfall. and the PM_2.5 mass concentration can be reduced by about 1/4 in the convective rainfall process of 3 h or more. The raindrop spectrum in the central urban area of Chongqing conforms to Gamma distribution, and there is little difference in the scavenging coefficient of aerosol particles in different spectral types of stable rainfall. The scavenging coefficient of aerosol particles in convective rainfall with maximum hourly rainfall ≥20 mm is significantly higher than that of other convective rainfall.