The invention discloses an automatic anti-sinking lifesaving system for ships, and belongs to shipbuilding, ship repairing or ship accessories. Enough extra stability, wind resistance and reserve buoyancy can be provided for a ship, the reserve buoyancy can be rapidly and automatically released to make the ship float in the initial stage of ship sinking, and it is guaranteed that the ship is stable and does not sink. The system is characterized in that the main structure of the ship is not changed, and stabilization, stability maintenance and anti-sinking lifesaving effects can be provided ina full-time and all-around mode only by additionally arranging steel stability maintenance balance fins, a permanent floating body, a safety air bag, an automatic monitoring controller and a high-pressure air supply system. High-strength flexible synthetic fiber sandwich net cloth serves as a stress framework of the air bag, and PVC airtight coatings are arranged on the two faces of the cloth. Theair bag is rigidly fixed on the ship body by using a surrounding binding type binding band. The triple methods of a hanging pendulum type automatic sensing controller, remote liquid pressure sensors,floating ball liquid level switches and manual operation are used, so that full-time and all-around automatic sensing control is achieved, and life and property safety of the whole ship and all people on the ship is guaranteed.