Abstract: Marine unmanned electromechanical systems such as marine environment sensors and vehicle/robots can be used for marine military reconnaissance, resource exploration, ecological monitoring, and status monitoring of large marine equipment and facilities, which is beneficial to marine ecological protection, marine economic development and protection of marine rights and interests. Long term effective energy supply is a bottleneck problem that restricts the operation of marine unmanned electromechanical systems in vast sea areas. The battery has limited power and pollutes the environment, while cable power supply not only has high costs but also limits the mobility of marine unmanned electromechanical systems. Wave energy is one of the most abundant renewable energy sources. The conversion of wave energy into electrical energy can be used for self-powered sensing, control, and driving of marine environmental electromechanical systems. It has the advantages of sustainability, flexibility, convenience, energy conservation, and environmental protection, and is expected to break the energy supply bottleneck of marine unmanned electromechanical systems. In addition, as fossil fuels face depletion and serious environmental problems, the development of marine energy can alleviate energy crises, reduce environmental pollution, and promote economic development. This paper comprehensively discusses the research progress of wave energy harvesting, self-powered marine unmanned electromechanical system based on wave energy harvesting and marine unmanned electromechanical system, discusses the key challenges and looks forward to it, provides a multi-dimensional reference for solving the long-term effective energy supply problem of marine unmanned electromechanical system, promotes the development and application of self-powered sensing, control and drive technologies, and helps the application of marine unmanned electromechanical systems in far-reaching sea areas.