A regional climate model (RegCM3) and a large-scale routing model (LRM) are employed to investigate the effects of land use and land cover change on climate and runoff of the Yangtze River basin in China. The RegCM3 is nested within ERA40 reanalysis data. Two 15-year simulations (1987－2001), one with current land use and the other with potential vegetation cover without human intervention over China, are conducted. The runoff outputs of the RegCM3 simulations are used to drive the LRM to study the land use and land cover change on streamflow of the Yangtze River. The analysis shows that the current land use changes have large influences on the hydrological variables such as precipitation, evapotranspiration, surface runoff depth and streamflow, but have not evident influences on surface air temperature. The land use changes lead to increased streamflow over the main stream of the Yangtze River in summer and the increment is more in the lower reaches, while at Datong station the change rate of the streamflow is close to 15%. Overall the land use changes in the Yangtze River basin may intensify the hydrological cycle of the basin, which should increase summer precipitation and streamflow.