Abstract: Investigation is performed of the space/time features of MODIS data retrieved aerosol optical thickness in the east and middle of China in 2001 and MM5 simulation is conducted of the forcing of sulphate aerosol on direct radiation and its climate effect. Evidence shows that optical thickness is greater in the Sichuan Basin, middle-lower reaches of the Yangtze, Huanghe-Huaihe valley, Guangdong and Guangxi and varies on a seasonal basis, with its maximum in spring. The response of surface temperature to forcing exhibits distinct features on a regional and seasonal basis, with marked temperature drop in the south (north) of the target area in winter, spring and autumn (summer); in terms of regional mean, the forcing is –34.53, –22.76, –22.56 and –20 W/m² in spring, winter and autumn, in order under a clear sky for the eastern and middle part and in terms of the drop in surface temperature the study region shows –0.65, –0.37, –0.34 and –0.09oC in winter, autumn, spring and summer, respectively.