On the basis of the CTD data gathered by the-R / V Science I in each Oct. of 1986-1988 and the winter averaged temperature anomaly in southeast China, the interannual variability of the Western Boundary Current (WBC) is examined in terms of volume transport by inverse calculation and its role in the climate is studied by statistical method.The estimated transport is 50,20, and 33 x 106 m3 / s for the Kuroshio and 24,34, and 36 x 106 m3 / s for the Mindanao Current (MC)in October of 1986,1987, and 1988, respectively.The WBC is the biggest channel in the ocean for transporting heat poleward and plays an extremely important role in establishing and maintaining the global heat balance. Results showed that meridional heat transport by the Kuroshio northeast of Luzon apparently dominates coldness or warmness in winter in southeast China.Two phenomena observed in the western Pacific but not in the western Atlantic are the warm pool and the equatorward flowing MC which, together with the North Equatorial Counte On the basis of the CTD data gathered by the-R / V Science I in each Oct. of 1986-1988 and the winter averaged temperature anomaly in southeast China, the interannual variability of the Western Boundary Current (WBC) is examined in terms of volume transport by inverse calculation and its role in the climate is studied by statistical method. The estimated transport is 50,20, and 33 x 106 m3 / s for the Kuroshio and 24,34, and 36 x 106 m3 / s for the Mindanao Current (MC) in October of 1986, 1987, and 1988, respectively. The WBC is the biggest channel in the ocean for transporting heat poleward and plays an extremely important role in establishing and maintaining the global heat balance. Results showed that meridional heat transport by the Kuroshio northeast of Luzon apparently dominates coldness or warmness in winter in southeast China. Two phenomena observed in the western Pacific but not in the western Atlantic are the warm pool and the equatorward flowing MC which, together with the North Equatorial Counte