Abstract: With grid wind data for low latitudes from May through July, 1979, an analysis in this paper of the mean daily meridional circulation for the areas of East Asia monsoon found that the establishment processes of summer monsoon circulation in East Asia was considerably different from that in India. The former, made up of monsoonal circulations in both the subtropics and the tropical South China Sea, began at an earlier time. The subtropical monsoonal circulation is associated with the Southerlies from the subtropical South Asia and the northern upper Easterlies; whereas the monsoonal circulation in the tropical South China Sea is related to the cross-equatorial current from Australia and the southern upper Easterlies. The summer monsoon circulation in India was established somewhat later, accompanying with the Somali low jer and the northern upper Easterlies. The structures of the two systems are different from each other in that the monsoonal circulation in East Asia is a quasi-meridional cell while that in India a quasi-zonal one.