Abstract: Data of the past 4 decades are used to analyze in much detail the SST variations for the South China Sea and their influence on the rainfall in Guangdong Province. The variations take place in periods between 25-32 months, 8 months behind those for the eastern Pacific as shown in lag correlation analyses. The anomaly of SST in the South China Sea occurs mainly in February-July.In Guangdong, the annual mean rainfall is greater in warm water years than in cold water years, though differences exist from month to month in the year.It is found that the SST in the South China Sea intensifies and attracts the westward extension of the subtropical high in warm water years, but weakens its eastward return in cold water years.