Abstract: Successive measurements of tidal current were carried out at 16 stations in the radial sand ridge area of the South Yellow Sea off the Jiangsu coast.Using the methods of harmonic tidal analysis and tidal-induced current calculation,we calculated the tidal-induced residual current at every observation station.The results indicated that the tidal-induced residual currents are quite big in the radial sand ridge area,but rather small in the distant area offshore.There is a semi-closed tidal current moving in a clockwise direction in the radial sand area.