Through analyzing the hydrodynamic sediment conditions, remote sensing and seabed evolution,mathematical models of tidal current and sediment, wave models of SWAN, mild-slope equation and Boussinesq equation, physical model test of erosion by tidal current and wave, calculation of sedimentation and calculation of sudden sedimentation, etc., we studied the hydrodynamic sediment problems in the development of deepwater port in radial sandbanks, Rudong county, Jiangsu province. The research results show that the development of deepwater port in radial sandbanks is feasible with necessary technical measures taken.