Abstract: The effects of the critical height of Qing hai-Xizang Plateau uplift on the atmosphere have been studied by using P-σ incorporated coordinate general circulation model system in this paper. Numerical experiment results show that there is a critical height during the course of Qinghai-Xizang Plateau uplift, which is near 1.5 km in summer. When the average height of the Plateau uplifting surpasses this critical height, a series of changes in general circulation and climatic elements will occur. The uplift of the Plateau changes the air flow pattern ar ound the Plateau. The deep and steady Plateau monsoon appears. There are maximum sensible centers over the western Plateau. The rainbelt and precipitation amount will be also changed obviously.