Abstract: Based on the information data of land use, soil classification, hydrology and meteorology, a SCS model, developed by Soil Conservation Service (SCS), U.S.A., was applied to simulate the rainfall-runoff relationship in Wangdonggou small watershed. The results show that: first, Wangdonggou watershed was compartmentalized into some sub-units according to natural draining division, and the table of CN values fitting for Wangdonggou watershed was proposed; second, the hydrograph of calculated runoff process using the SCS model and the hydrograph of observed runoff process coincide very well in height as well as shape, and the model is of high precision above 75%. It shows that the SCS model can effectively be used to simulate the runoff generation and the runoff process of typical watershed in Loess Plateau, which meanwhile, suggests that the SCS hydrological model is one of good means and a main developing direction to study the rainfall-runoff relationship based on the geographical or remote sensing information.