This paper analyzes the both 20-year simulations by MM5V3 regional climate model,which is nested in one-way mode within ECHAM5 general circulation model.Two sets of 50 km grid spacing simulation for present climate (1981-2000,real CO₂ scenario) and mid-21^st century climate (2041-2060,IPCC A1B scenario) over China are conducted.Present climate simulation results show that MM5V3 model has the better capability to simulate the spatial patterns of surface air temperature and precipitation when comparing to ECHAM5 model,though in most areas surface air temperature is underestimated and precipitation is overestimated.The climate change simulation by MM5V3 under IPCC A1B scenario indicates that the seasonal mean surface air temperature will increase 1.2-3.9 ℃ in mid-21^st century,with a stronger trend in winter and the increasing magnitude from south to north.The seasonal precipitation undergoes a significant change as well.Autumn and winter mean precipitation will remarkably increase with a range of 10% to 30% over most parts of China.Meanwhile,spring and summer mean precipitation will increase in southern China and decrease in northern China both about -10% to 10%.Furthermore,the changes of surface air temperature and precipitation also have the inter-annual characteristics.Annual mean surface air temperature indicates the increasing trend in all sub-regions,with the increase rate by 0.7-0.9 ℃/10 a.The variability of surface air temperature will increase in all sub-regions.Annual mean total precipitation also shows the increasing trend in all sub-regions except Northwest China.