Abstract: By analizing data of 1979 it is shown that there is a stable monsoon vertical circulation cell over the Changjiang-Huaihe Reaches in eastern China.The circulation cell is very clear on the average map of monsoon period. It's meridional scale is about 1500km with a top up to 100 hPa. At vertical direction its centre can be found about 7-9 km from surface. The ascending air of the cell coincides with the Meiyu rain belt. The existence, maintenance and decay of the cell influence the evolution of Meiyu directly. In this case no closed inverse circulation cell is found to the north of the average monsoon circulation cell.It is also shown through a thermodynamic analysis that the Qinghai-Xizang Plateall heating in early summer has a close relationship with the evoluting of the monsoon vertical cell and the formation of Meiyu.