Abstract: A climatic and hydrological nesting model system was established to simulate the climate and hydrology conditions under the SRES A2 scenario and assess impacts of climate change on water resources in the Lanjiang basin. Two sets of 30-year integral experiments i.e. the control experiment and the future prediction experiment, were conducted in the Eastern China by using the 20 km high resolution regional climate model RegCM3 coupling with the atmosphere part of global climate model FvGCM. The results of the control experiment from 1961 to 1990 indicate that both the simulated annual averaged temperature and precipitation in Zhejiang province have distinct topographic characters and agree with the observations since the detailed topography of Zhejiang province is incorporated into the high resolution RegCM3. The simulated annual averaged temperature of Lanjiang basin is quite consistent with the observed one, but the simulated annual precipitation is less than the observed, especially in summer. In the future prediction experiment, the climate change scenario of Lanjiang basin from 2071 to 2100 was set up under the SRES A2 scenario. Then the distributed hydrological model DHSVM was calibrated and validated using observed data. The hydrological model could reproduce the past runoff process of Lanjiang basin quite well, reflecting its high modeling ability. At last, the two sets of simulated results by RegCM3 were put into DHSVM to drive the hydrological simulation in Lanjiang basin. The simulated results show that the averaged temperature in each month will all rise from 2071 to 2100 compared to the one from 1961 to 1990, and the annual temperature will increase by 2.84 ℃ . The annual precipitation will also increase especially in the flood season from April to July, which could results in the rising of flood frequency in the basin. The annual runoff will also increase in step with more annual precipitation, especially in the flood season. Under the global persistent warming scenarios, the climate extreme events such as high temperature, heat waves and floods will probably be more severe in the basin.