A multifunctional floating breakwater includes: a plank platform, a first buoy, a second buoy, a first wave baffle, a second wave baffle, a first arc breast wall, a second arc breast wall, upper inclined supports, lower inclined supports and a net cage. The multifunctional floating breakwater integrates a floating breakwater and a wave-energy power generation device, which can not only maintain good stability of the water surface in a harbor, but also generate electric energy, and allow for aquaculture and other activities as well, and has advantages of being movable and not limited by water depth and geology. In addition, the invention has a simple structure, easy production and maintenance, no pollution to the marine environment and therefore wide application prospects.