By employing CCM3-RegCM2 nesting model which is developed on the base of NCAR CCM3 and RegCM2,the influences of surface conditions over the midwest Tibetan Plateau on summer precipitation in China are studied.The results show that the temperature gradient over the northern Plateau is strengthened as a result of surface albedo and temperature of the west-central Tibetan Plateau increasing if the vegetation over there are damaged,and the westerly jet should move to farther north and west to prevent the north cold air from reaching in the Yangtze River and the Huanghe River Basins so that the rainfall reduce in those areas,meanwhile,the anticyclonic circulation over the Tibetan Plateau which is enhanced by the increasing of air temperature would change the air stream direction from southwesterly into westerly in the Yangtze River.At the same time,subtropical high moves towards west and north and dominates the Yangtze River,leading to the summer precipitation decreasing in China.