Based on the fluid mechanics basic equations and gas-liquid mixing coupling calculation equations，the section accumulated by rocks generated randomly was meshed in refinement using finite difference method.Based on CFD software，the simulation model on wave action of mound breakwater was established and the boundary condition was set in accordance with the actual situation strictly to gain an accurate gas-liquid mixing coupling calculation.Simulation results of pressure and flow lines distribution in and around the mound breakwater and strength of rocks indicate that the water depth has an effect on inlet area，pressure and flow lines distribution；the pressure difference of front and back side of the breakwater is necessary for transfusion inside of breakwater；lager local porosity and gap connection degree result in lager transfusion degree and strength of the rocks blocking in flow lines is lager as the conflict between water and rocks.