The hydrologic cycle research under changing environment is one of the hot topics in water science study.The study on the response mechanism to hydrological process changes is of great practical significance to future water resources planning and management. In this study,based on the Budyko hypothesis,we conducted attribution analysis of the streamflow changes in the Zoige basin by sensitivity analysis,and the results showed that:the sensitivity coefficients of streamflow to precipitation,potential evapotranspiration,and catchment characteristic parameter were 0.654 1,-0.234 7,and-182.205 0,respectively,which means that every 1mm increase in precipitation would induce a 0.654 1mm increase in streamflow;every 1mm increase in potential evapotranspiration would induce a 0.234 7mm decrease in streamflow;every increase of 1in the catchment characteristic parameter would induce a 182.205 0mm decrease in streamflow.The streamflow of the Zoige basin showed a significantly decreasing trend.Compared with the reference period (1960-1990),the streamflow of the change period(1991-2011)decreased by 56.23mm(20.48%).The main influence factor was the change of underlying surface characteristics,whose contribution rate reached 93.46%.The climate change only contributed 5..57%.