[Objective] Bailongjiang Watershed was selected as a case to study the spatiotemporal change of ecological carrying capacity(ECC) and its driving mechanism from the perspective of land use change for the purpose of the ecological environment management and sustainable development of the watershed.[Methods] Based on the theory of ecological footprint, the spatial and temporal changes of the ECC of the watershed during the latest 25 years were analyzed by the remote sensing data and transfer matrix analysis method from 1990 to 2014.[Results] ① On the time scale, the ECC of watershed during the latest 25 years changed with a general trend of "decrease-increase-decrease", but had different trend for different land use type. ② On the spatial scale, the watershed ECC showed an uneven spatial distribution:the area with higher value located in the northwestern and southwestern parts, and the area with low value located in the northeastern parts; the higher of the altitude and gradient, the higher of ECC. ③ From 1990 to 2002, 2002 to 2010 and 2010 to 2014, the change of the watershed ECC varied frequently with apparent transfer, respectively.[Conclusion] The watershed ECC fluctuated increasingly while the ecological quality was improved during the latest 25 a. The spatial pattern of the watershed ECC changed with obvious spatial heterogeneity due to the landform characteristics and land use/cover change, the grain for green project also affected the change of watershed ECC.