[Objective] In order to understand and prevent the soil erosion in the upper reaches of the Yangtze River correctly, and to provide scientific basis for preventing and controlling the soil and water conservation, Shangnan County of Shaanxi Province, which is in the source of the Yangtze River, was taken as an example for analyzing the spatial distribution of soil erosion.[Method] Based on the Landsat TM7 and ETM⁺ images, the information of land use in Shangnan County in 2010 was obtained. Using the revised universal soil loss equation(RUSLE), the present situation of soil erosion in Shangnan County was quantitatively evaluated and studied.[Results] The main land use type in Shangnan County is forest land, accounting for 87.05% of the total area of the county, followed by cultivated land(9.43%), the residents(2.82%), water(0.64%), unused land and grassland(0.06%). Soil erosion of Shangnan County in 2010 is serious because of the slope land and low covered forest grassland, and the average erosion modulus was 4953.76 t/(km²·a). The erosion area(worse than light erosion) reached 1319.3 km², accounting for 57.03%. The total area of intensity erosion and more intensity erosion accounted for 24.10%, followed by the light erosion area, which accounted for 14.31%. The area of middle erosion and most intensity erosion accounted for 6.23% and 12.39% respectively. The area of most intensity erosion and intensity erosion is mainly distributed in the slope land of the northern, central and southeastern mountain area. Although the area ratio of most intensity erosion and intensity erosion is not very high, they has the biggest contribution to the total erosion amount of the county, up to 52.29%.[Conclusion] Inappropriate land use is the main cause of serious erosion. Therefore, the main object for the prevention in Shangnan County is the slope land of the northern, central and southeastern mountain area.