Studying on the impacts of climate change and anthropogenic activities on runoff at the watershed scale is the basis for watershed management planning and achieving sustainable management of river basins.Xinshui river watershed, a typical watershed in the Loess Plateau, was selected as the study area. The M-K test method was used to analyze the trends of annual evapotranspiration, precipitation and runoff from 1958 to 2015. The double mass curve method was carried out to identify the abrupt point. Ecological hydrological analysis method and water balance principle were conducted to quantify the respective contribution of climate change and human activities on annual runoff. The annual runoff showed a significant decrease trend (Z=-5.84, p<0.000 1), however,nonsignificant trends were detected for precipitation (Z=-0.72, p=0.31) and potential evapotranspiration (Z=-0.5, p= 0.88). The muttionpoints of annual runoff were 1974 and 2000, respectively. Compared with the baseline period, the runoff reduction from 1975 to 2000 was mainly attributed to climate change. The contribution rate of climate change to runoff reduction was 73.14%, whereas the contribution rate of land use change was 26.86%. Contrarily, the runoff reduction from 2001 to 2015 was mainly ascribed to land use change. The contribution rate of land use change for runoff reduction was 103.81%,which indicated that land use change has become the main driving factor for the runoff variation in the Xinshui river watershed. It is necessary to develop land use plans rationally for realizing the coordinated development of water and soil resources in the Xinshui River Basin for river basin management in the future.