The low frequency oscillation(LFO)of the East Asian summer monsoon vertical circulation and its relationship with monsoom activities are analyzed in this paper using the ECMWF data from June 1 to September30,1984,indicating that significant local LFO exists in both the vertical meridional circulation and equatorial zonal circulation and that the LFO of the East Asian monsoon meridional circulation originated from the LFO vertically moving in the middle and upper troposphere at 30°S. The LFO in the southern and northern hemispheres are linked by the LFO of the meridional circulation. Besides,the possible relationship between the LFO of the tropical monsoon and Meiyu occurrence is discussed.