The numerical simulations of tidal current and sediment are carried out after the implementation of the project of Hongkong-Zhuhai-Macao bridge. The piers are treated as solid boundary and the grids near the piers are enriched. According to the results of the numerical simulation, the changes of tidal level, velocity of tidal current,tidal volume and the siltation and erosion of the underwater topography in nearby sea area after the implementation of the project are analyzed. The results show that the effect of constructing Hongkong-Zhuhai-Macao bridge in the hydrodynamic sediment environment is only limited to the vicinity of the bridge, and it has no negative effect on Lingding navigational channel and has no influence on the patterns of swale of Lingdingyang bay.