Soil erosion can result in land degradation and sediment deposition of a river,where soil erosion is connected with some natural factors and human activities.Using ArcView 3.2 and Arc/Info 8.1 as the work platform,relations between soil erosion and terrain slope,between soil erosion and land use/land cover,between soil erosion and soil types of Lancang river basin in Yunnan Province are analyzed according to the results of map layers intersection and statistics analyzing.Finally,soil erosion of 1 km wide buffers of river and road in the same area is also studied.