Based on the data obtained in the area southwest of Kyushu in the summer of 1987 , the temperature-salinity distribtutions and circulation characteristics are described and the origin of the Tsushima Warm Current is analysed. Based on the data obtained in the area southwest of Kyushu in the summer of 1987, the temperature-salinity distributions and circulation characteristics are described and the origin of the Tsushima Warm Current is analyzed.