The Qinghai-Tibet Plateau is an ecotone of high altitude, dry climate and less vegetation species. Thus, in order to realize the thriving regional development, control water pollution and distribute the water resource optimally, it is important to predict the meteorological and hydrologic data accurately. With the complement of the Coupled Model Intercomparison Project Phase 5(CMIP5), several climate change scenarios are used to simulate the meteorological and hydrologic data, however the resolution of the output results is around 0.5°, which is so rough that increases the uncertainty of the simulation results. Thus, the study analyzed the meteorological data of the Xining and Menyuan stations from the year of 1958 to 2011 to learn the data trending and mutation; and the relations between the observed data and the large-scale predicted factors and SDSM down-scale method were used to predict the meteorological data. The predicted precipitation was conducted by the GRNN model. The SWAT model of the Huangshui Basin was established by the simulated meteorological data to simulate the hydrologic data under the climate change scenarios, and the precise simulated results were obtained. It was predicted that the temperature of the studied region would become flatter on the existing basis; the precipitation would have a great increase in the wet season from May to September. Besides, the runoffs of the Huangshui Basin would have a decrease with the increase of the carbon emissions under different Representative Concentration Pathways (RCP) scenarios.