The invention discloses an emergency anti-sinking and anti-overturn gas bag for a ship. The emergency anti-sinking and anti-overturn gas bag comprises a gas bag module and a gas inflation device. The gas bag module comprises a bag body, a base, an outer coating and a gas inflation hose. The gas inflation device comprises a high-pressure gas bottle and a pipe system. High-pressure nitrogen is injected in the high-pressure gas bottle. The pipe system comprises a high-pressure nitrogen main pipe, a pressure reducing valve, a one-way valve, a solenoid valve and a gas inflation hose connector. A high-pressure gas bottle head valve is connected with the pressure reducing valve, the one-way valve, the solenoid valve, the gas inflation hose connector and the gas inflation hose through the high-pressure nitrogen main pipe. According to the technical scheme, the refitting difficulty of the device to the ship is low, and the feasibility of achieving engineering is high; refitting of a hull is less, so that normal sailing of the ship cannot be affected after refitting, and the influence on original performance of the ship is less; and the device is simple in structure, reliable in working, not high in cost and suitable for being popularized.