Globally, ecosystems in arid and semi-arid regions are particularly susceptible to the effects of desertification. As a typical arid and semi-arid region in China, and the main source of wind and sand for Beijing-Tianjin-Hebei, the ecosystem condition of the Otindag Sandy Land has a direct impact on the ecological and socio-economic stability of China's northern regions. Deepen understanding of the ecosystem health (EH) in sandy areas facilitate the improvement of local environmental management. In this study, we quantitatively measured the EH during 2000 to 2020, and analyzed the effects of groundwater and land-use types on EH in combination with a geographically weighted regression (GWR) model. The results demonstrate that: 1) The Otindag Sandy Land demonstrates a distinct east-west gradient in EH, with elevated values concentrated in eastern zones. From 2000 to 2020, high-EH areas expanded by 14% (12 % to 26 % of the total area), reflecting intensified environmental recovery efforts. 2)Temporal characteristics revealed a 34.62 % increase in mean EH values (0.26 to 0.35) between 2000 and 2020. Kernel density estimation further indicated a spatial homogenization trend in EH distribution, suggesting reduced geographic disparity over the study period.3) The GWR analysis indicated a significant and positive correlation between the water budget and EH, with EH demonstrating particular sensitivity to the water budget in the southeastern part of the sandy area.