Circulation in China Seas has been investigated by Chinese oceanographers in some detail for many years. However, owing to data being sparse and scarce, studies were basically concerned in interseasonal (mainly summer and winter) fluctuations and almost none was in the interannual variability of the circulation in China Seas.It is pointed out that the routine (monthly or bimonthly) hydrographical section data on the continental shelf of China Seas accumulated since 1975, can be used to examine the interannual variability of the shelf circulation. An example is given to show there is interannual variability of shelf circulation in the East China Sea. And what is more, a hypothesis is proposed to describe where the interannual variability comes from and to explain why it is strongly correlated with El Nino events.It is strongly suggested that the interannual variability of the shelf circulation in China Seas be studied, as a strategy, with the routine hydrographical survey, which should be seriously conti Circulation in China Seas has been investigated by Chinese oceanographers in some detail for many years. However, owing to data being sparse and scarce, studies were substantially concerned in interseasonal (mainly summer and winter) fluctuations and almost none was in the interannual variability of the China Seas .It is pointed out that the routine (monthly or bimonthly) hydrographical section data on the continental shelf of China Seas since 1975, can be used to examine the interannual variability of the shelf circulation. An example is given to show there is interannual variability of shelf circulation in the East China Sea. And what is more, a hypothesis is proposed to describe where the interannual variability comes from and to explain why it is strongly correlated with El Nino events. It is strongly suggested that the interannual variability of the shelf circulation in China Seas be studied, as a strategy, with the routine hydrographical survey, which should be seriously conti