[Objective]The study aimed to simulate the runoff of Shitoukoumen Reservoir basin by using SWAT model. [Method] Based on DEM elevation, land use type, soil type and hydrometeorological data, SWAT model, a distributed hydrological model was established to simulate the monthly runoff of Shitoukoumen Reservoir basin, and the years 2006 and 2010 were chosen as the calibration and validation period respectively. [Result] The simulation results indicated that SWAT model could be used to simulate the runoff of Shitoukoumen Reservoir basin, and the simulation effect was good. However, the response of the model to local rainstorm was not obvious, so that the actual runoff in June and July of 2010 was abnormally higher than the simulation value. [Conclusion] The research could provide theoretical references for the plan and management of water resources in Shitoukoumen Reservoir basin in future.