Abstract: Based on the statistical analysis,the average number of typhoon in the Western Pacific Ocean (include the South China Sea) in E1 Nino years is less than normal while in inverse E1 Nino years the situation is reveresed.Associating the generating conditions of typhoon with the fluctuations of the atmospheric circulation and SST in the Western Pacific in E1 Nino years and in inverse E1 Nino,some qualitative explanations for the influence of E1 Nino on the typhoon activity in the Western Pacific Ocean are discussed.