Using the observational daily precipitation data in South China during 1961—2012,this paper analyzes statistical characteristics of persistent heavy rainfall during the first rainy season in South China under the background of Pacific sea temperature fields on different time scales,and discusses the responses of low frequency cycle of precipitation during the first rainy season in South China to different sea surface temperature forcing,which can promote the development of extended-range forecast of the persistent heavy rainfall.Results show that there are higher occurring probability,stronger intensity and longer duration for the typical persistent heavy rainfall in the PDO(Pacific Decadal Oscillation) cold phase years than in the PDO warm phase years.Under the background of Pacific sea temperature fields on different time scales,the characteristics of the persistent heavy rainfall are different.During the PDO cold phase years combined with significant sea surface temperature anomalies in Nino region in winter and spring,the persistent heavy rainfall are stronger and longer.The external forcing of Pacific sea surface temperature fields on different time scales might have relationships with the low frequency cycles of precipitations during the first rainy season in South China,and further affect intensity and duration of the persistent heavy rainfall.