Abstract: Based on mean monthly OLR data, the characteristics distributions of convective activities over middle and low latitude are analyzed in relation to flood/drought during the first rainy season in south china. The results show that the sea near Philippines is a key area where convective activities affect the rainfall during the season, another key area is equatorial central-eastern Pacific. The OLR anomalies in last winter over the warm pool of tropical West Pacific is a strong signal in earlier stage of flood/drought. The direct impact of Hadley circulation over East Asia and Pacific on the flood/drought is revealed. In order to know the causes of flood/drought formation, some further analyses are made for the dynamic structure of atmospheric circulation of the Northern Hemisphere responding to the convective activities over the sea near Philippines, and the possible ways of the influence of East Asia and Pacific teleconnection wavetrain on flood/drought during the first rainy season in south China are also discussed.