The Uplifting of QinghaiXizang Plateau is a very important geological event in the geological history. It very clearly influences the forming and changing of the arid climate and environment in drought area of Northwest China. The CCM3 is used to simulate the differences of the precipitation and temperature over NW China among before, during and after the QinghaiXizang Plateau is uplifted. From the researches, we can simply study the influence of the Plateau uplifting on the climate change in NW China. The results show that the uplifting of QinghaiXizang Plateau can clearly effect on the precipitation of the area. The annual precipitation is more about 150 mm than now before the Plateau is uplifting. And following Plateau is uplifted up, the precipitation is reducing. When the Plateau uplifted up to the critical height, the annual precipitation is reduced about 77 mm, but it is still more than now about 73 mm. The changes of the precipitation are different in different seasons.