Abstract: In this paper,the distribution of the divergence and the vertical velocity of 500 hPa high and the evolution of the atmospheric heat source over the Qinghai-Xizang Plateau are comPuted,and the variation of the vorticity,the zonal flow at 100 hPa level and the vertical meridional cell are also analyzed.The results are as follows:A notable descending motion produced due to divergence in the lower troposphere and convergence in the upper troposphere exsists in the 500 hPa high over the QinghaiXizang Plateau in summer.During the active periods of 500 hPa high,the convective heating will be restrained,and the heat sink appears in the atmosphere over the Qinghai-Xizang Plateau.As a result,the 100 hPa south Asia High.is weakened and will likely transform from east pattern to west pattern,and its long axis moves northward.Furthermore,the westerly jet situated north of the Qinghai-Xizang Plateau is weakened,the northern branch and the southern branch of easterly jet situated south of QinghaiXizang Plateau are weakened and merged into a single whole,50 the southwest monsoon intruded into food of the Qinghai-Xizang Plateau is weakened too.on the contrary,the ascending motion situated over the Bay of Bengal is developed into stronger.Its convective heating will play an important role in the maintenance of the easterly jet and the south Asia monsoon