Abstract: In this paper, using the daily grid data of the ECMWF/WMO, we made the composite analysis on 12 mediumrange variation processes of the subtropical high over the western Pacific in summer during 1980—1983. It is found that there is the subtropical monsoon circulation cell over East-Asia. We also discussed its features. The results show that the subtropical monsoon circulation cell is formed through the following process: when one divergent updraft driven by the condensation heating of the continental monsoon rain belt in East-Asia was moving southward, it met another one moving northward from Nanhai sea, and then these two currents has a confluence, and formed a downdraft over the subtropical area. And, it plays an important role in summer circulation over East-Asia