In terms of 1979-1994 NCEP/NCAR re analyses and OLR data,the variation characteristics of tropical convective activities are investigated and the relationships between the interannual variation of summer OLR and East Asian summer monsoon(EASM) are discussed.It is found that the interannual variation of summer OLR is remarkable in warm pool and the equatorial central Pacific,which is in anti phase oscillation.When the convective activities are strong(weak) in warm pool and weak(strong) in the equatorial central Pacific,the EASM is strong(weak) and the rainbelt is north(south) of its mean position with less(more) precipitation in the Yangtze River reaches.Further evidences show that the atmospheric circulation anomaly in subtropical Asia(tropical Pacific) relative to the dipole tropical convective activities is vertically barotropic(baroclinic).