This study deals with the general numerical model to simulate the two-dimensional tidal flow, flooding wave (long wave) and shallow water waves (short wave).The foundational model is based on nonlinear Boussinesq equations.Numerical method for modelling the short waves is investigated in detail.The forces, such as Coriolis forces, wind stress, atmosphere and bottom friction, are considered.A two-dimensional implicit difference scheme of Boussinesq equations is proposed.The low-reflection outflow open boundary is suggested.By means of this model,both velocity fields of circulation current in a channel with step expansion and the wave diffraction behind a semi-infinite breakwater are computed, and the results are satisfactory.