Abstract: It is found that the close relationships are present between westerly index in middle and low latitudes of the Southern Hemisphere, pressure index of equator and the medium-range activities of West Pacific subtropical high and typhoon group in summer (from May to August) of the Northern Hemisphere by analyzing the data of general circulation of the Southern and Northern Hemispheres for six years. In the active years of typhoon group the variation of general circulation begins at middle latitudes of the Southern Hemisphere, and then at low latitudes of the Southern Hemisphere and equator, the pressure index of equator reaches low value. After that, a series of variations of West Pacific subtropical high over the Northern Hemisphere would appear. The transportation period of the variations mentioned above would be quasi-two weeks.