The Taiwan Strait is a very important sea region for ship-sailing and fishery activities, but the current data in the Strait are very scant up to now. In this paper, based on the historical data at hand, the co-relative relations between the monthly average surface currents in the Strait and the monthly M. S. L. differences across the Strait, the monthly M. S. L. differences across the Strait and the monthly M. S. L. at the western coast were analysed. The resu1ts show that a positive co-relative relation of sufficient significance exists between the former two sets data, and while a negative co-relative relation of relative significance exists between the latter two sets data. Therefore, it is possible to forecast the tendency of variations of the monthly average surface current in the Strait according to the monthly M. S. L. at the western coast (for example, Amoy). These empirical relations may be useful for the study of the tendency-forecast of the current in the Strait.