Abstract: With the monthly precipitation, seasurface temperature (SST), outgoing longwave radiation (OLR), sea surface pressure for 28 years, the particularities of the airsea interaction in East Asian summer monsoon region have been revealed through the diagnostic methods including the concurrent anomaly correlation analysis, the leadlag correlation analysis, and the regression analysis. It is found that attributed to the eruption of the East Asian summer monsoon, the phase relationship between precipitation and SST over the Pacific warm pool, South China Sea, and Kuroshio Current region alters from the positive correlation (the ocean dominates atmosphere primarily)in the spring, autumn and winter into the negative correlation in the summer (the atmosphere dominates ocean primarily). The possible mechanisms through which the atmosphere dominates ocean are analyzed, and the importance of each mechanism over different ocean regions is also discussed.