In this study,rotated principal component analysis and complex Morlet transform were used in analysing observed weekly rainfall in China during 1982～1995 and NMC weekly mean SST in related oceans during 1982～1994.Results showed that the annual variations of SST and rainfall are mainly caused by the return movement of vertical incident point of sun light between the Tropics of Capricorn and Cancer and the annual variations of cloud and fog coverage over seas.According to the rainfall annual cycle,China can be reasonally divided into 12 rainfall regions,where the annual variations of rainfall are basiclly dependent on the annual variations of sun radiation strength,effective sunshine rate and Asian summer monsoon.EI Nin~o has an obvious influence only on the north of the Great Bend of the Yellow River and Guangdong and Guangxi provinces;the annual variation of SST in east of warm pool has a certain influence only on the north of the Great Bend of the Yellow River.