Aiming at effect of berm on the top level of rubble mound breakwater，based on the breakwater project of a new port，the paper analyzes and compares the empirical formula calculation results about mean wave overtopping and top level，and also makes a comparison between the empirical formula calculation results and physical section model test results. The results of empirical formula show that mean wave overtopping of breakwater with berm could be reduced effectively when the top level is same，and the results of empirical formula and physical section model test study shows that the top level of rubble mound breakwater with a berm can be significantly reduced.