Based on IPCC AR4 outputs simulated by multimodel for 20th century and future projection under SRES B1,A1B and A2 green emission scenarios,the surface air temperature changes in the 21st century are analyzed.It is revealed that the surface temperature presents different spatial and temporal features over China.Annual mean temperature will rise by 2549 ℃ at the end of the 21st century under 3 Scenarios,and the enhancement magnitude is larger than global mean.In addition,the warming magnitude in winter will be larger than in the other seasons,the annual range of temperature is expected to decrease in the future.The projection results are consistent between the different emission scenarios and models in the first half of the 21st century,with the warming magnitude being 088092 ℃.However,the projected temperature becomes more sensitive to the scenarios and models since mid of the 21st century.By the end of the 21st century,the temperature will increase by about 244428 ℃.Relative to 1980—1999,annual mean temperature over China will rise by 2 ℃ around 2050,then the temperature will increase more quickly under SRES A1B and A2 scenarios and reach or exceed 3 ℃ at the end of 2060s.The temperature changes differently with regions,and the year of temperature rise above 2 ℃ in Southern regions will be later for about 1030 years than that in Northern regions over China.Affected by the rising temperature,Northeast China and Northwest China will be the most sensitive regions in the future.