Qinghai Lake basin is a key area to maintain the ecological security of eastern Tibetan Plateau. Projections of climate change in Tibetan Plateau and SWIM (soil and water integrated model)are used to predict potential changes in runoff depth, evapotranspiration and deep percolation at Buha River Basin in three periods of the future (2016-2035, 2046-2065, 2081-2100). Monthly runoff simulated by SWIM is found to correspond well with measured values. Therefore SWIM model can be applied to alpine regions. With increase in precipitation and rise in temperatures, runoff depth and evapotranspiration will continue to increase up to 2100. In addition, deep percolation will decline initially then recover and rise. The impact of climate change on hydrological processes varies in different seasons. Impact on deep percolation concentrates in July and August, effect on runoff depth and evapotranspiration is seen between June and August. Some spatial differences in hydrological processes are present. Increase in runoff depth will concentrate in the upstream and downstream areas, whereas actual evapotranspiration changes significantly in the middle and upper reaches. Further, deep percolation will rise slightly in parts of the upstream and estuaries, but will decline in the middle reaches. These results will be useful for water resources management and watershed conservation.