Abstract: On the platform of ArcGIS analysis and ERDAS spatial modeler,the spatial characteristics of soil erosion in Guishui River watershed were analyzed.The factors of slope,vegetation coverage and land use are selected as main ecological background factors and the soil erosion intensity index(SEI) is chosen as the integrative method.The results show that mild slope,low vegetation coverage and sparse forest,which are exactly the characteristics of the piedmont alluvial fan areas,are the spatial background of the soil erosion.The mild slope,low vegetation coverage(excluding urban constructed areas) and sparse forest are mainly within the piedmont alluvial fan areas in the watershed.The effective protection measures were finally put forward.