The invention discloses a seaborne cylindrical floating body recycling device, relating to the technical field of ocean and shipbuilding. The seaborne cylindrical floating body recycling device comprises a ship crane, wherein a lifting winch and a high-pressure gas storage tank are arranged on a lifting arm of the ship crane; a hose is arranged at a gas outlet of the high-pressure gas storage tank; the lifting winch is connected with a floating body recycling cover through a steel wire rope; one end of the hose is connected to the floating body recycling cover. Compared with the prior art, the seaborne cylindrical floating body recycling device has the advantages that the structural design is reasonable, the operation is easy, and cylindrical floating bodies vertically floating in the sea can be safely and efficiently recycled and cannot be damaged, so that the recycling rate is high.