Nangang industrial zone in Tianjin is located on a typical muddy coast in Bohai Bay，and an inner branch channel connecting to the Dagang channel is proposed to be built in its eastern basin. To predict the siltation of the channel，we establish a numerical model of sediment transport coupling with wave-current interaction，choose the spring tide data measured at the site as the representative tidal and the energy-weighted average of measured wave data from nearby observation station as the representative wave，and verify the model by the annual siltation data of the adjacent 150，000-ton waterway of Tianjin Port. On the basis，we apply the numerical model to calculate the sediment transport of the sea area of Nangang industrial zone，and predict the annual sedimentation along the branch channel of the east basin. The results show that the siltation mainly occurs in the entrance section of Nangang industrial zone and the first half part of the branch channel in the east basin.