Abstract: The annual flow over the upper reaches of the Heihe River shows increasing in the recent 42 years, which is extremely significant in winter, but all in all, it is relatively stable, the conversion of abundant and rare year is fairly balanced. Precipitation is the primary factor to impact the flow of the upper reaches of the Heihe River, the increasing of precipitation is closely related to the increasing of flow in summer, and the increasing of flow in summer impacts the increasing of annual flow. The ascending of air temperature, especially in autumn, 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, especially in summer, and also makes the depletion of ground water resource increasing, and has a elimination function for the annual flow increasing caused by the precipitation.