The magnitude of the wave height in the port has a significant impact on the mooring stability conditions.This article takes an offshore chemical terminal overseas as the engineering background and takes the new type of densely packed pipe piles breakwater as the research object to explore the transmission performance of the breakwater under different wave conditions.Based on the finite difference method of FLOW 3D，a three-dimensional numerical wave tank with a free water surface is established.The accuracy of the model is verified by comparing it with the experimental data.The results show that as the wave period increases，the transmission coefficient first increases and then tends to flatten.When the incident wave period exceeds a certain range，the protective effect of the breakwater on the waves is no longer enhanced.Under small-period wave conditions，the transmission coefficient increases with the increase in the width of the pile gap.When the relative width of the pile gap is 0.05，the transmission coefficient is less than 70%.The research results can guide practical engineering applications.