[Objective] The temporal and spatial variation of water resources and ecological environment in Hexi Corridor as well as their spatial and temporal correlation from 2003 to 2015 were analyzed in order to provide scientific basis for promoting reasonable development and utilization of water resources and realizing sustainable development of production, life, and ecology in the study area.[Methods] Based on the GRACE gravity satellite, TRMM precipitation, and MODIS vegetation index data, this study investigated the spatiotemporal variations of water resources and ecological environment as well as their interaction mechanisms in the pixel, watershed, and region levels, using the linear regression and correlation analysis.[Results] The annual water storage in the Hexi Corridor and its three watershed areas presented a downward trend with the highest decline rate in the Heihe and Shiyang basins. There had nonsignificant trend in the precipitation in the study area, and the vegetation presented an increasing trend. The monthly water storage was positively correlated with monthly precipitation and NDVI. The annual water storage was independent of annual precipitation, while it was highly negatively correlated with annual averaged NDVI, and this relationship presented apparent spatial heterogeneity and scale dependent.[Conclusion] The rapid and continuous increase in the artificial vegetation, especially in the cultivated land, accelerated the water resources consumption and caused the decrease in annual water reserves in study area.