According to the feature of the project and the sea area, by TK-2D software and with irregular triangular grid, an integral mathematical model and a local refined one near project area of tidal current and sediment in Lingdingyang bay are set up. Verification and validation are carried out fully against measured data and numerical simulations of tidal current and suspended sediment field are made. The features of the tidal current field and the suspended sediment field of the Lingdingyang bay area are analyzed and the basis is established to demonstrate the effect of constructing Hongkong-Zhuhai-Mocao bridge on the sea area.