Abstract: This study investigated the variations in precipitation, temperature and runoff in the upper Yellow river under the changing environment. A Delta method was used to downscale the BCC-CSM1.1 model data of Global Climate Models (GCMs) to establish future climate scenarios, and a VIC distributed hydrological model to simulate the future runoff process. The results show that the long-term mean annual precipitation will increase by 4.31% to 5.74% under different climate scenarios in the next 40 years (2011-2050) compared with the baseline period (1971-2010). And the long-term mean maximum and minimum temperature will increase by 1.04 ℃ to 1.61 ℃ and the increases in winter will be more distinct than in the other seasons. Under three different scenarios, the increase in annual runoff will be 2.65%, 2.66% and 8.07% respectively, but the increasing rate shows a decreasing trend. Seasonally, winter runoff will increase while summer runoff decrease.