Though the upper ocean response to strong wind forcing, especially the passage of typhoon in summer, is of fundamental importance for understanding the mixing process of the surface low salinity waters in the East China Sea, the related study has been limited by the lack of direct observations. Recent deployments of satellite tracked drifters equipped with temperature and salinity sensors in the East China Sea provided a good data set to analysis the ocean response to the passage of typhoon. In August 2004, when Typhoons Rananim, Megi and Chaba passed over the East China Sea, seven drifters were deployed in the area southwest of Cheju-do by a Korea-Japan cooperative work. The drifters were generally moving to 30-50° right of the wind direction. The drifter movements changed sharply two days before the typhoon and the flow field pattern changed for a week after the typhoon passage. Three consecutive circular patterns in drifter trajectories indicating inertial motion with about 15 km radius appeared after the passage of Typhoon Megi.