Abstract: The relationship between typhoon activity in the northwest Pacific and El Nino and La Nina events is analyzed with statistical and composition methods. It is indicated that there are fewer frequent typhoon activities in El Nino years but more frequent typhoon activities in La Nina years. The start and end time and intensity of El Nino and La Nina events also have influence on typhoon formation. The typhoon activity statistical characteristics supply information that might be used in seasonal prediction. Using singular value disassemble(SVD)method, the relationship between 500hPa height and SST fields is also analyzed. The result shows that the sea-air-coupling interaction in El Nino and La Nina years causes abnormal frequency of typhoon activities.