The north operation area of Lanshan port area in Rizhao Port is planned to add LNG wharf,and three plans for the layout of supporting waterway and breakwater project are put forward.Numerical simulation method is used to calculate the flow velocity of the harbor basin and channel under different schemes,especially at the entrance.The calculation results show that:after the construction,the velocity of each point in the harbor basin decreases under the protection of breakwater;under the influence of the overtopping action of the breakwater,the cross flow velocity at the entrance position reaches the maximum;in scheme 2,the flow rate is relatively small and the duration of flow rate greater than a certain value is relatively short.On the basis of scheme 2,a section of breakwater is optimized to be a diversion breakwater.As a part of water can be passed through the diversion breakwater,the cross-flow of channel near the breakwater head is reduced.