[Objective] The objective of this study is to reveal the response mechanism of runoff to land use changes in Shiyang river, in order to provide theoretical basis for reasonable allocation and optimization of water resources in arid areas.[Methods] Using various data derived from watershed DEM(digital elevation model), land use, soil and meteorology and combined with GIS(geographic information system) and RS(remote sensing) technology, we developed a distributed hydrological model with SWAT(soil and water assessment tool). Based on SWAT Model and SUFI-2 algorithm, we simulated monthly hydrograph in the Shiyang river basin from 1980 to 2009.[Results] The top three sensitive parameters influencing model were CN₂, Alpha_Bf and Timp. The simulated values of calibration and validation periods were in accordance with actual values, Nash-Sutcliffe and R² efficiency coefficient E_ns were higher than 0.8, the relative errors|R_e|were all less than 10%.[Conclusion] The result of the present work implied that the SWAT model of SUFI-2 algorithm is suitable for the simulation of the monthly runoff in Shiyang river basin.