[Objective] This study conducted rechecked division of key preventing and controlling area of urban-type soil erosion at county-level, to provide support for deep development of the prevent and control methods of soil erosion at county-level.[Methods] According to the key factors such as land use status, soil erosion intensity, vegetation coverage extracted from ArcGIS and eCognition, we explored the soil erosion division with regard to key prevention area and key control area in Xigu District, Lanzhou by combining qualitative and quantitative methods, and top-down and bottom-top methods.[Results] The district has characteristics of small jurisdiction, large population, developed economy, small proportion of the primary industry, land use fragments, serious soil erosion, potential erosive harm and others. We determined the qualitative and quantitative index of the above two areas:two key prevention areas and two key control areas.[Conclusion] ① Our main efforts of soil and water prevention should be pay to the upstream hilly regions to prevent downstream cities from being suffered erosion. ② Forest close and natural revegetation should be taken into effect in the mountains that have abundant rainfall. ③ Farm mechanization should be developed to increase the income of farmers.