The hydrology and sediment environments in the ocean area near the project are analysed firstly.Then,a two dimensional model of wave,tidal current and sediment transport is seted up and fully verificated to study the tidal and sediment transport law after the channel project,which analyses the tidal current characteristics,entrance flow state,cross flow in channel,influnce of area aroud,tidal level change and diversion ratio of the five waterway entrance.