[Objective] The soil erosion prone area in the plain river network region of Zhongshan City was dividedfor the implementation of soil and water conservation law and the protection of precious soil and water resources in order to provide the scientific basis for the government to administrator according to law and implementation of the water and soil conservation management of production construction projects.[Methods] Through the analysis of natural characteristics of the region, such as weak soil erosion resistance, easy weathering of parent rocks, heavy rainfall with uneven distribution during the year, abundant water and heat conditions, and social and economic characteristics such as strong social and economic activities of human beings, GIS & RS technology is used.[Results] By dividing soil and water conservation zones, the range of plain river network areas, where soil and water was easy to lose, was defined. The sensitive factors of soil and water loss such as landform, rainfall, soil, vegetation are determined in Zhongshan plain river network area. Also, the index system of soil erosion prone area division is constructed by selecting quantitative and qualitative indexes, and the soil-erosion-prone area in the plain river network area of Zhongshan City is divided.[Conclusion] The soil erosion prone area in the plain river network area of Zhongshan City which includes Xiaolan town, Huangpu town and other 9 townships, whose land area is about 666.92 km², accounting for 37.39% of the total land zone of the city. The achievements in the division of soil erosion prone area can improve the planning system of soil and water conservation in Zhongshan City, and also can provide a scientific basis for the compilation of soil and water conservation planning at the prefectural level or for the formulation of rules and regulations.