The Regional Climate Model version 3(RegCM3) is used to investigate the effect of black carbon(BC) aerosol on regional climate in China.The influences of BC aerosol on the radiative forcing,air temperature,and rainfall are analyzed.The simulation result shows that BC aerosol produces a positive radiative forcing at the atmosphere top,and a negative forcing at the surface in the region.Adding of BC aerosol causes distinct changes in surface air temperature in the continental area of China,and the changes show obvious seasonal characteristics.The surface temperature increases in most regions in January,whereas it increases in northern China and decreases in southern China in July,and it does not change significantly in April and October.The result also shows that BC aerosol emission leads to the increase of summer rainfall in the mid and lower reaches of Yangtze River,but results in rainfall reduction in some regions of northern China.