The water source area of the middle route project for south-to-north water transfer in Shaanxi Province is a severe soil erosion area that may affect the diverted water quality.To ensure the diverted water quality in the project,the present situation of soil and water loss and the influence factors are analyzed based on the historical data and the remote sensing interpretation data.By analyzing soil erosion degree and various factors influencing soil and water loss,some specific and effective measures for controlling soil and water loss were put forward.