By using the hydrological and meteorological observation data,the variations of flow and its climate causes are analyzed in this paper. The results show that the surface water resources show n a decreasing trend at the rate of 1. 4 * 10~8 m~3·(10a)~(-1),the conversion of abundant and rare year is fairly balanced. The annual distribution of runoff was homogeneous. Annual runoff concentrated mainly in June - September in Zoige region,accounting for 60% of the annual runoff. Hydrological process has a bimodal phenomenon in year,mainly related to the plateau climate characteristics. At the same time the domain runoff concentration degree and concentration period all showed a trend of decline. Precipitation is the primary factor to impact the flow of the Zoige. It shows that precipitation in summer determines the runoff,and the autumn runoff response to rainfall is the most sensitive. The ascending of air temperature,causes the enlargement of snow melting of high mountain,and therefore makes flow increase during the non-flood period,which accelerates the river basin evaporation,and also makes the depletion of ground water resource increasing,and has a elimination function for the annual flow increasing caused by the precipitation.