Based on SWAT Model and SUFI-2 algorithm, combined with GIS and RS technology, runoff responses to land use change in Ganjiang Basin were analyzed quantitatively using various data derived from watershed DEM, land use, soil and meteorology in this paper. It was concluded that the top three sensitive parameters influencing model were ALPHA_BF, CN2 and ESCO, respectively. The simulation values of calibration and validation periods were in accordance with actual values, R² and Nash-Sutcliffe efficiency coefficient E_{NS were higher than 0.90, the relative errors |Re| were all less than 3%. Forestland, paddyland and grassland took about 85% of the total area of Ganjiang Basin from 1990 to 2000. In the same climate condition, monthly, annual runoff manifest obviously consistent trends under two different land use scenarios, the annual runoff in 2000 is slightly larger than that of 1990 on the whole. Compared with 1990, runoff of the subbasins increases significantly in the east, southeast, southwest region in 2000. The growth of development land, irrigated land and bare rock, reduction of forest area are likely the main factors causing the increase of water production.}