The urgent demand for energy structural reform and the limitations of single energy development have promoted the combination of wind energy and wave energy. A hybrid energy system means that two or more energy devices share the same foundation. It reduces the levelized cost of energy (LCOE) and improves competitiveness through infrastructure sharing and increased power output. This paper starts with the development of the joint resources of wind and wave energies, then introduces the foundation forms of the hybrid system. It reviews the latest concepts and devices proposed with the integration of wind energy and wave energy, according to the foundation forms, and makes a preliminary assessment of the synergies of the hybrid system. The existing study methods of the hybrid systems are summarized. In view of the challenges faced by the development of hybrid energy systems, several suggestions are put forward accordingly. This paper provides a comprehensive guideline for the future development of the hybrid wind-wave energy converter (W-WEC) system.