The western pipeline of PetroChina has, at present, the longest transportation distance among the petroleum pipelines in China. Because the pipeline was paved mechanically, original landform, top soil and vegetation were destroyed, which reduced soil anti-erodibility and caused soil and water loss.The natural sit-uation was firstly summarized and then, soil and water loss and its impacts on ecological environment were analyzed for the pipeline in Gansu Province.The "three synchronous steps" principle must be insisted on.In addition, the measures should be taken according to the following policies, such as the combination of com-prehensive control with comprehensive exploitation, scientific allocation of control measures, and prevention of soil erosion newly occurred