In recent years, with the acceleration of China"s economic construction and the rapid development of urbanization, the large-scale agglomeration of industry and population has caused the rapid expansion of impervious surface, which has a serious impact on the urban ecological environment. As a key indicator of urbanization level, impervious surface has been widely used in urban ecological environment assessment. In order to quantitatively analyze the temporal and spatial dynamic characteristics of the impervious surface expansion in the Erhai River Basin, this paper takes the Erhai River Basin where Dali City is located as the research object, and uses the Landsat 5 and Landsat 8 remote sensing images of Dali City from 2005 to 2017 to extract the normalized water body. The index (MNDWI) and the normalized difference impervious surface index (NDISI) spatially analyses the cities and roads in the Erhai River Basin and extracts the impervious surface information for spatial pattern analysis. The results show that with the rapid development of urbanization from 2005 to 2017, the vegetation coverage and water coverage of the Erhai River Basin are declining, while the impervious coverage rate rises from 11.6% to 19.8%, showing a rapid and sustained upward trend. From linear fitting results of Erhai water quality and impermeable coverage in the basin, it can be concluded that there is a certain negative correlation between them. It can be predicted that the future development of Erhai water quality will decrease with the increase of impervious coverage. Therefore, at the same time of urban development, we should pay attention to the comprehensive management of Erhai Lake and not allow the water quality to adjust itself. The results of this study provide reference information for urban planning management and watershed (water) environmental management in Erhai watershed, and have important practical significance.