Abstract: Blue-green landscape is an important part of ecosystem, which is of great significance to the protection of biodiversity and ecological security.This study selected Nanchang, a typical water network city in the south of China, as the study area. A combination of landscape ecology models and spatial analysis methods was adopted to quantitatively assess the evolution of blue-green landscape patterns and habitat quality. The spatio-temporal response relationship between urban habitat quality and blue-green landscape change was explored.Results show that: (1) The frequency and breadth of conversion between blue-green landscape and cultivated and construction lands increased significantly from 2005 to 2020. The aggregation degree of blue-green landscape in the ecological barrier area was at a high level, and the blue-green landscape in the central urban area continued to shrink and become fragmented. (2) Habitat quality in Nanchang declined from 2005 to 2020, and could be characterized by regional differentiation of “Peripheral high, middle low”. For the study period, the high-grade habitat areas were mainly distributed in the urban ecological barrier areas; The low-grade habitat areas in the central urban area demonstrated the characteristics of river-crossing expansion, southward expansion and internal filling. (3) The effects of landscape pattern of blue-green landscape on habitat quality were spatially heterogeneous and directional. Aggregation Index (AI) was positively correlated with habitat quality in general, but the positive effects of Edge Density (ED), Interspersion and Juxtaposition Index (IJI) and Patch Density (PD) on habitat quality were mainly concentrated in cultivated and construction lands. It is concluded that regulation of the blue-green landscape pattern is one of the effective ways to promote habitat quality. Under the background of rapid urbanization, the reasonable lay out of the blue-green landscape in central urban area should be put into practice in water network cities, aiming to strengthen the protection of the integrity of the blue-green landscape in the ecological barrier area, and construct the ecological pattern of the blue-green landscape. The results provide scientific reference for the ecological security of water network cities and the realization of the pattern of “water-land symbiosis, and resilient development”.