Disclosed is a combined structure of a fishing net cage and floating wind turbine foundation. The combined structure includes a wind turbine and a polygonal deep-sea fishing net cage floating body. The polygonal deep-sea fishing net cage floating body comprises an upper polygonal floating body frame, a bottom ring beam, and a middle truss structure, and a connecting column disposed between the upper polygonal floating body frame and the bottom ring beam. A connection structure of the wind turbine set is disposed on the upper polygonal floating body frame. The bottom of the polygonal deep-sea fishing cage floating body is provided with an interface connected with a steel cable of a mooring system. A sub-tank capable of providing ballast by loading water and buoyancy is disposed in the polygonal deep-sea fishing net cage floating body.