Dianchi Lake has been listed as the focus of national river bodies harnessing,which attracts special attention in the conservation of the nine major plateau lakes in Yun'nan Province.Non-point source pollution is regarded as the primary cause of pollution of Dianchi Lake,whereas soil erosion,which accounts to 80% of the pollution amount,is the source of non-point source pollution. This paper introduced the integration of GIS with USLE,and usage of the spatial analysis of GIS and the algorithm of each factor of USLE to estimate the amount of soil erosion in the Baoxiang watershed.Results showed the annually averaged amount of soil erosion was 983.51 t/km²,which was in the category of low-grade erosion.The none or slightly eroded area occupied 91.5% of the watershed area,and contributed 52.80% sediment in watershed.The middle and the upwards eroded area only occupied 8.5% of the watershed area,but contributed 47.2% sediment.