China is facing two major problems from energy shortage and environmental pollution due to the rapid development of economy. The exploitation of clean and renewable energy brings hope to China. Owning wide seas, China is rich in offshore wind energy and current tidal energy. This paper considers installing turbines on the platform of the generator of floating wind turbines, designing a floating co-generator of wind and tidal current to achieve co-generation of wind turbines and turbines. Firstly, this paper conducts a preliminary design of three-column floating wind-current generator. Then this paper uses the GeniE and HydroD modules of SESAM to model the co-generator and perform stability analysis. Finally, based on the Catenary Theory, this paper designs mooring system for the co-generator and uses AQWA to perform time-domain analysis, ensuring the steady operation of the co-generator at working seas.