The breakwater is an important barrier to a wharf，and its high investment often becomes the key factor of scheme decision-making in the feasibility study stage of a project. For optimal design of the breakwater for a wharf project in eastern Guangdong，we collect the measured offshore wave data near the project. On this basis，we establish the transformation relation of wave elements between offshore wave measuring area and wharf front area considering the numerical simulations of waves. In this way，we can obtain the operational time corresponding to different schemes，which can provide reliable data for decision-making of the breakwater construction scheme. The results reveal that offshore waves incident in the same direction have the same transformation coefficient. This feature can be used to simplify the statistical work of operational time and improve the efficiency of scheme selection.