In the regulation project of returning port shoreline to beach,in order to maintain the stability of man-made shore, breakwater should be built in the engineering sea area.Taking the regulation project of returning port shoreline to beach in Rizhao Port Shijiu port area coal storage yard as an example,based on the model of MEPBay,this paper analyses shore stability under various schemes of breakwater,and calculates the sediment movement after the project.The calculation result shows that the beach stability can be maintained by reasonable breakwater location and length.If the breakwater is short,the south side of the beach will be more seriously eroded.Otherwise,the north side of the beach will be more seriously eroded and the south side of the beach will be muddied.