According to the standard of soil erosion classification and grade,th e author discusses the methods of carving up polygons, capturing the values of f actors of impressing soil erosion, and differentiating erosion intensity on the GIS(Geographic Information System). The result and reasons based on the comprehe nsive evaluation on the basic polygon and on the multi-coverage overlay are ana lyzed. The author thinks that two methods can be used for differentiating the er osion intensity, and the latter can reflect the differences of soil erosion amon g small parts. From the technique and save of the manpower,money and material r esources, the multi-coverage overlay is better method when the digital maps of factors exist.