The invention discloses a ship anti-overturning device. The ship anti-overturning device structurally comprises a hull and a ship anti-overturning device body. The ship anti-overturning device body isarranged at the bottom of the hull in an interference fit mode. The ship anti-overturning device body is composed of a rectangular steel frame, a center keel and a telescopic anti-overturning devicebodies, the rectangular steel frame is internally provided with the two telescopic anti-overturning device bodies, and the two telescopic anti-overturning device bodies are evenly distributed on bothsides of the center keel. The two telescopic anti-overturning device bodies are axial symmetric structures, and the telescopic anti-overturning device bodies are arranged on the two sides of the shipanti-overturning device body. A ship that needs to be stabilized at low speed or mooring state can control the telescopic anti-overturning device bodies through a control room, so that the telescopicanti-overturning device bodies can be opened in a stretching mode and attached to the water surface by using balance floating plates, the contact area between the hull and the water surface is increased, so that the ship can still maintain a stable state at low speed or mooring state, the safety and stability of the ship during sea voyage are improved, and the ship is effectively prevented from rolling over and overturning. .