[Objective] The dynamic changes in grassland habitat quality and its influencing factors in Xilingol League, Inner Mongolia were studied to provide a scientific theoretical basis for the formulation of ecological environmental protection policies and high-quality development in this area.[Methods] The remote sensing ecological index (RSEI) was constructed by using the Google Earth Engine (GEE) platform and MODIS data to evaluate the habitat quality of the study area. Spatial heterogeneity and influencing factors of RSEI were analyzed by using the Moran index and geographic detector.[Results] ① The results demonstrated a temporal change in habitat quality in the study area, with quality initially deteriorating and later improving from 2000 to 2021. The ecological environment significantly improved over time. Habitat quality was better in the typical steppe of central China and the meadow steppe of Eastern China, while it was worse in the desert steppe of Western China. ② The global Moran's I for the five-year study period exceeded 0.935, indicating a strong positive spatial correlation in the distribution of RSEI within the study area, primarily characterized by high-high and low-low cluster patterns. ③ The geodetector results showed that greenness was the main factor affecting RSEI. The most significant influence on ecological environmental quality was the interaction between model factors and natural factors, followed by the coupling of model factors and socio-economic factors.[Conclusion] The areas of high-value habitat quality in the eastern region of the Xilingol League should continue to strengthen protection of the ecological environment, and the areas of low-value habitat quality in the west should focus on restoration and management of desert grasslands and on curbing the eastward expansion of desert.