Abstract: There are a lot of sea entering channels in Jiangsu coastal zone,and they are charged with functions of flood control and drainage in seaside district and hinterland. At present,sedimentation of tidal channels downstream of sluices is universal and serious. What′s more,with the rapid development of tidal flat reclamation,sedimentation becomes more and more serious. As an example,based on coastal geomorphology,estuary & coastal hydrodynamics and sediment hydraulics,Wanggang tidal channel is taken to study the influence of tidal flat reclamation on channel sedimentation downstream of tidal stuice in Jiangsu coastal zone was studied,and the allowable maximal tidal flat reclamation area is brought forward.