Abstract: Investigating the spatial and temporal changes of regional ecological environment quality is helpful to provide guidance and coordination for the protection and improvement of local ecological environment. Based on the Landsat remote sensing data from 2005 to 2020, the spatial and temporal changes and influencing factors of ecological environment quality in Mojiang Hani Autonomous County were explored by using the Remote Sensing Ecological Index (RSEI) and the Geo-detector model. The results showed that: (1) the average values of RSEI in the study area in 2005, 2011, 2015 and 2020 were 0.5689, 0.5824, 0.5866 and 0.5985, respectively, showing an increasing trend year by year. (2) In 2020, more than half of the area in the study area will be rated as excellent and good, but the ecological environment management of the basin still needs further improved. (3) The change of eco-environmental quality in the study area was influenced by multi-factor interaction. The dryness and heat factors had the greatest explanatory power for the spatial distribution of eco-environmental quality.