With the increasing demand for floating breakwaters in coastal engineering and offshore operations in recent years，we propose a new type of floating breakwater with wing plates. Based on the three-dimensional potential flow theory，we calculate and analyze the wave suppression performance of the new floating breakwater，and compared it with the common box-type floating breakwater. It is proven that the new floating breakwater has better wave suppression performance for waves of longer periods. The influence of the cross-sectional parameters of the wing plate floating breakwater on the suppression performance shows that：1）The larger the box width and the deeper the draft，the better the wave suppression performance of the new breakwater. Besides，the longer the wing plate and the smaller the angle，the longer the wave period of best wave suppression performance. 2）Appropriate adjustment of the section parameters can make the floating breakwater with wing plates adapt to more wave environments and add more applicable scenarios.