[Objective] This study investigated the rainfall, runoff, land use changes during the period of 1995-2016 in the upper reaches of Sancha river basin, the water source area of the Qianzhong hydraulic project. The impacts of land use change on runoff were explored in order to provide a reference for predicting future changes of the water resources in the basin and the allocation of water resources in Qianzhong hydraulic project.[Methods] The relationship between rainfall and runoff was analyzed by conventional linear regression and result simulation. The impact of land use change on runoff was studied by using the land use dynamic change index and transfer matrix.[Results] The rainfall and runoff in the upper reaches of Sancha river watershed fluctuated and declined during the past 20 years, and the evolution processes could be divided into two stages:1995-2010 (stageⅠ) rainfall and runoff showed a downward trend. 2010-2016 (stageⅡ) rainfall and runoff showed a downward trend, but the decline of runoff was greater than rainfall. Since 1995, the land use change in the basin was obvious. The area of grassland and woodland increased by 5.33% and 3.63%, respectively. The cultivated land decreased by 6.92%. The dominant changes in land use types were conversion from cultivated land to forestland, grassland and construction land. In addition to the impact of rainfall, land use change was the major factor affecting the continuous decline of runoff. During the period of 2010-2016, the area of grassland and woodland increased by 19.93% and 5.25%, while the cultivated land and unused land decreased by 13.93% and 87.97%, respectively, indicating that land use change was the main reason for the significant decrease in runoff. In addition, the construction of Pingzhai reservoir in the Qianzhong water control project had an important impact on the reduction of runoff to a certain extent.[Conclusion] Land use change in the upper reaches of the Sancha River was closely related to the changes of runoff, which reduced watershed runoff.