In order to master the hydrodynamic and sedimentary variation of the water area front the sluice after the extension of intake channel,we systematically analyze the hydrodynamic and sedimentary processes with the changes of the surrounding shoreline when the sluice is opened and closed,which are based on the fixed-point observed data during the flood season and spring tide (June 17-19,2015) in the intake channel of the downstream reach of Sanjia Port sluice.The results show that,with the regulation projects being constructed recent years,the reach has been propagated downstream about 1.3 km,and there are double low-velocity zones in the intake channel caused by berthing ships and shoal.The intake channel front sluice is controlled by tide,and tidal current is rotational flow.The hydrodynamic of intake channel is weak when the sluice is closed,and the velocity in upstream reach is slower than 0.1 m/s.The sediment transports to upstream.The distributions of sediment concentration and the instantaneous flow velocity are both single peak when the sluice is opened,but the velocity decays rapidly.