In order to investigate the spatial distribution and driving mechanism of ecological quality in the Shule River Basin, a remote sensing ecological index (RSEI) for evaluating the ecological quality of the basin was constructed by coupling the greenness, humidity, heat and dryness indices. The RSEI was utilized to evaluate changes in ecological environmental quality in Shule River Basin from 2000 to 2020, and the geodetector was employed to detect the primary factors driving these changes. The results indicate that the greenness and wetness indices positively contribute to improving the ecological environment within the basin, while the dryness and heat indices negatively exacerbate it. From 2000 to 2020, the ecological environmental quality of Shule River Basin gradually worsened from high altitudes upstream to low altitudes downstream, yet overall, the basin's ecological environmental quality exhibited an improving trend. Generally, precipitation plays a significant role in influencing the ecological environmental quality of Shule River Basin at high altitudes, while land use type has a crucial impact on changes in ecological environmental quality at low altitudes. Furthermore, over time, the explanatory power of human factors for changes in the basin's ecological quality has been increasing.