Eight experiments have been conducted with a barotropic numerical model to study the Kuroshio system and eddy phenomena in the East China Sea. The study has basically simulated the branching features of Kuroshio in the East China Sea (the Taiwan Warm Current and the Tsushima Warm Current) and the flowing path of the Kuroshio itself. Also the Huanghai Warm Current and the cyclonic gyre south of the Jizhou Island have been reflected in the model experiments. Moreover, the model has predicted the possible existence of a weak cyclonic gyre around 27?N, 124?E and the branching relationship of the southward current along the west coast of Kyushu of Japan with the Tsushima Warm Current. Investigations on their dynamics have given out some explanations to the forming and flowing mechanism of these flow characteristics appearing in the model experiments. Eight experiments have been conducted with a barotropic numerical model to study the Kuroshio system and eddy phenomena in the East China Sea. The study has basically simulated the branching features of Kuroshio in the East China Sea (the Taiwan Warm Current and the Tsushima Warm Current) And the flowing path of the Kuroshio itself. Also the Huanghai Warm Current and the cyclonic gyre south of the Jizhou Island have been reflected in the model experiments. Moreover, the model has predicted the possible existence of a weak cyclonic gyre around 27? N, 124? E and the branching relationship of the southward current along the west coast of Kyushu of Japan with the Tsushima Warm Current. Investigations on their dynamics have given out some explanations to the forming and flowing mechanism of these flow characteristics appearing in the model experiments.