A two-dimensional numerical wave flume model was set up using the open source CFD software OpenFOAM to solve the continuity and momentum equations for viscous incompressible fluid based on fluid finite volume method. The numerical wave flume was verified by the experimental data of wave elevations, pressures and the bottom velocity from the physical model test of a baffle structure under regular waves. The transmission coefficients and the bottom velocity of the battle structure in different incident wave conditions were computed and compared alone with the relative depth. It shows that the transmission coefficients can be less than 0. 5 if the relative depth is greater than 0. 8. The bottom velocity of the oscillating flow can obviously be enhanced with the increase of the relative depth and extra attention should be focused on by engineering technicians.