Kunming is the capital city of Yunnan Province and a bridgehead city facing South Asia and Southeast Asia. With the rapid development of Kunming‘s economy and society, the urbanization rate continues to increase, and the quality of the ecological environment in this area is also changing rapidly. How to quickly and accurately obtain the temporal and spatial pattern evolution of Kunming‘s ecological environment quality and explore the driving factors is of great significance to the realization of ecological environmental protection and sustainable development of Kunming. In this paper, the Google Earth Engine (GEE) platform is used to use the long-term Landsat remote sensing image data to mask the water body, extract greenness, dryness, humidity and heat, and construct the remote sensing ecological index RSEI through PCA. Using spatial analysis methods such as cold and hot spot analysis and center of gravity migration to explore the evolution of the spatio-temporal pattern of ecological environment quality in Kunming from 2000 to 2019, and use single-factor analysis and interactive detection in geographic detectors to analyze its internal driving forces. The results show, (1) From 1995 to 2019, the quality of the ecological environment in Kunming showed a trend of first increasing-then decreasing-then increasing. The overall ecological environment quality was in a general state in the past 25 years, but the ecological environment continued to improve. (2) In the past 25 years, the ecological environment quality grade area of Kunming City is, medium ecological environment area > good ecological environment area > poor ecological environment area > poor ecological environment area > excellent ecological environment area. From the perspective of spatial distribution, the ecological environment quality presents The spatial distribution pattern of high in the southwest and poor in the northeast. (3) From 1995 to 2019, the centers of the standard deviation ellipse of Kunming‘s ecological environment were relatively close to each other, and the major axes all showed a south-north direction. (4) In Kunming, the ecological environment quality is poor in areas with concentrated rocky desertification, concentrated water and soil erosion, concentrated population and rapid urban expansion, while areas with better ecological environment mostly have higher vegetation coverage. Population and slope are the human activity factors and natural factors that dominate the spatial distribution of ecological environment in Kunming, respectively. Slope, population and GDP, together with other factors, have a significant impact on the quality of ecological environment in Kunming. (5) In the future, Kunming City should rigorously prioritize the protection of key ecological areas, enhance ecological conservation and restoration efforts, optimize land use and development, continuously enhance the quality of the ecological environment, and achieve synchronous and sustainable development of the ecological environment and the economy.