Abstract: The alpine gorges in northwest Yunnan，important ecological reserves in China，are facing increasingly prominent environmental problems due to accelerated urbanization. Insights into the spatiotemporal changes in eco-environmental quality are of great significance for eco-environmental protection and construction in the alpine gorges of Northwest Yunnan. This study selected Landsat TM/OLI remote sensing images from 1990，1995，2001，2008，2015，and 2022 as the data source to extract four ecological indices：normalized difference vegetation Index （NDVI），wetness （WET），normalized difference bare soil index （NDBSI），and land surface temperature （LST）. Consequently，a remote sensing ecological index （RSEI） was constructed to assess and monitor the eco-environmental quality of the alpine gorges in northwest Yunnan from 1990 to 2022. The results indicate that from 1990 to 2022，the average RSEI in the study area showed a trend of an initial decline followed by an increase. Specifically，the RSEI reached its lowest value of 0.450 in 1995 and then increased continuously from 0.450 in 1995 to 0.604 in 2022. Over this period，the proportion of areas with excellent and good eco-environmental quality increased by 22.03%，while those classified as poor and very poor eco-environmental quality decreased by 14.49%. These variations were predominantly composed of improvements，covering 62.42% of the study area. Spatially，areas with very poor quality were primarily concentrated in agricultural areas，urban construction land，along the Jinsha River，low-altitude areas with sparse vegetation，and the slopes of landform intermontane basins （Bazi） in Heqing County. In contrast，areas with excellent quality were mainly distributed in high-altitude mountainous regions characterized by lush vegetation and minimal human disturbance. Moreover，the land use type was identified as the main driving factor influencing the eco-environmental quality in the study area. The strongest interaction was observed between elevation （X1） and land use （X6），exerting the greatest impacts on eco-environmental quality in the study area. Besides，areas with clay soils were dominated by poor and very poor quality. The magmatic rock areas displayed a clear trend of ecological deterioration，while the sedimentary rock area presented significant improvements. Conversely，the metamorphic and complex rock areas maintained relative stability.