Abstract: The construction of ecological civilization and low-carbon transformation in the Yangtze River Economic Belt (YREB) are the key tasks of high-quality economic development in China. Based on the data of carbon emission intensity of 1 069 counties in the YREB from 2005 to 2019, the development trend and spatial characteristics of carbon emission intensity were investigated using statistical methods of nuclear density estimation, Dagum Gini coefficient, standard deviation ellipse and exploratory spatial data analysis. The results showed that: (1) The carbon emission intensity of the counties under the jurisdiction of the YREB generally showed a steady downward trend. The  dispersion degree and absolute difference had also decreased, and the absolute difference had narrowed. The carbon emission intensity of the YREB as a whole and the counties under the jurisdiction of the upper, middle and lower reaches demonstrated multipolar polarization, but tended to weaken. (2) The overall difference of carbon emission intensity in counties under the jurisdiction of the YREB showed a downward trend, and the degree of regional imbalance was generally at a high level. The main contribution source of the overall difference is the hypervariable density, with an average contribution rate of nearly 40%, followed by the intra-regional difference, with an average contribution rate of about 33%, and finally the inter-regional difference. (3) The regional distribution of carbon emission intensity at county levels showed a spatial pattern of northeast-southwest trend, and its distribution center of gravity showed a trend of first towards southwest and then turning back to northwest. The mode of local spatial agglomeration was mainly "low-low" agglomeration, with more districts and counties mainly distributed in eastern Sichuan and southwestern Chongqing in the upper reaches of the YREB, majority of Hunan and Jiangxi in the middle reaches and majority of Hubei. Based on this, efforts should be made to promote emission and carbon reduction according to local conditions and urban policies. This aims to enhance the spatial linkage and coordination between districts and counties, and to optimize the government assessment and supervision and accountability mechanism to jointly help the high-quality development of the YREB.