The two important hydropower development bases in Sichuan, the Yalong River Basin and Dadu River Basin, were taken as examples to construct a comprehensive evaluation system for the degree of hydropower development, in which the spatial cluster analysis method was adopted using the statistical data of water resources and hydropower. The spatial relations between upstream and downstream and the overall level of watershed hydropower development indicators were combined based on watershed segmentation. The impacts of different hydropower development degree on ecological environment were analyzed considering the data of development plans, soil erosion, geological hazards, water quality monitoring and fishery resources. The results show that the spatial heterogeneity and local agglomeration of indicators, such as hydropower development density and hydropower development intensity, are obvious. The hydropower development intensity and the total installed capacity of the basin show a significant correlation with the change of the land use type in the reservoir area. The hydropower development indicators of different grades also show significant differences, indicating the rationality of comprehensive evaluation system for hydropower development.