Soil and water conservation in plain areas is often neglected. Actually, with the rapid development of industry and agriculture as well as communication, the small topography of plain areas has changed. Thus, many slopes of small collecting-water basins appear and lead to soil erosion. The paper emphasizes the study on the relationship between annual erosion modulus of soil and the seven factors which influence soil erosion. We apply stepwise regression (the fiducial degree is 0. 1) and get the equation as follows; y=7358. 00-1986. 07x2- 60. 51x7 R=0. 970. In the equation there are only two independent variables which are anti-scouring index (1/cm2) and content of physical clay particles ( % ) , so we merely need to find out two factors and the annual erosion modulus can be predicted. In addition, the paper also deeply discusses the anti-scouring index and indicates that it is a comprehensive index which reflects the ability for soil anti-erosion. In order to alleviate soil erosion, we should use biological and engineering measures, to enhance the anti-scouring index of soil.