Abstract: The spatio-temparal variations of hydrological components caused by land use change is of great significance for understanding of runoff generation process, and optimizing land use structure and water resources planning. Based on three scenarios of land use data in 1980, 2000 and 2015 this study systematically investigates the impacts of land use change on the spatial-temporal variations of major hydrological processes such as runoff generation, evaporation, infiltration and runoff from perspective of hydrological response unit, by applying the SWAT model in Ganjiang River Basin as an example. Results show that land use change of the basin during 1980-2015 was mainly reflected by the reduction of cultivated land and forest land as well as the increase of urban and rural construction land. The reduction of forest land and increase construction land mainly contributes to the increase of runoff generation and the decrease of evaporation and infiltration. Generally, land use change has a greater impact on local hydrological processes, while the integrated hydrological effects are significantly reduced at watershed scale due to the mutual transformation of land use types and their overlapping effects, . The modelling result revealed that the effect of land use change has caused to an increase of average annual runoff of by 2.33×108m3 in the Ginjiang River Basin, which is quite small with reference to the observed runoff reduction in recent years. On this basis, the runoff decrease of Ganjiang River was mainly affected by climate change and other human activities, especially dramatic increase of water utilization for industry and agriculture in the basin. It is concluded that hydrological modelling should fully consider the spatio-temporal variations of hydrological effects of land use change, and pay attention to the coupling of natural and social water cycles, only in this way can watershed hydrological processes be more truly reflected and the scientific basis for the optimization of land use structure and the efficient management of water resources in the river basin be better provided.