Based on the analysis of the hydrodynamic sediment conditions and seabed evolution in Tianjin port sea area,we use the mathematical models of wave,tidal current and sediment to study hydrodynamics and sediment problems of floating LNG terminal project.The change of tidal current field before and after the water intake and the influences of the construction of the breakwater on the flow field in front of the wharf are simulated and analyzed.At the same time,the deposition thickness in the harbor and waterway during normal years and a strong wind is given.Based on the data analysis,we can draw the conclusion that flood-releasing and waterlog-draining have no obvious effects on the sedimentation in the project area.