Under the support of the GIS technique, the occurrence and distribution of soil erosion were studied in the plain before the mountain of the Heihe river, using the ~(137)Cs technique. And the spatial distributing rules of soil erosion under the different land use background were investigated quantificational. By the spatial analysis of the ~(137)Cs intensity, that the intensity and district difference of the soil erosion can be revealed. Furthermore, the correlation between the soil erosion and the LUCC of the region was to be discussed. Results show that it was belong to secondary erosion that in the plain before the mountain in the middle part of Heihe river, and the average soil erosion rates in the past 38 years of grassland, cultivated land and waste-land were increased in turn. Moreover, grassland cultivated in large acreage will accelerate the soil erosion. Secondly, the soil erosion capacity of the grassland, cultivated land and waste-land were about 0.4 hundred million tons,0.2 hundred million tons,1.2 hundred million tons respectively. Thirdly, the soil erosion of the region was presented increased trend in recently twenty years, the west area of it was eroded more strong, that the cosmically exploitation of the soil in the south, were made the land of current region deteriorated, therefore, the evolutive trend to the waste were accelerated in the lower reaches of the river.