An object of the present disclosure is to provide a gas-electric parallel-serial hybrid marine power train system with LNG cooling, including a gas engine, an electric generator, a motor, a natural gas storage supplier. The gas engine is connected to the shaft belt motor through a gearbox, the motor is connected to the gearbox through a clutch, propellers are connected to the motor, and an engine cooling system and a fuel cell cooling system are connected to an LNG vaporization heat exchange apparatus; the electrical energy sources are the fuel cell, the electric generator and a storage battery. The arrangement of multiple power sources according to the present disclosure can meet ship requirements under various environments and circumstances, improve operating efficiencies of the gas engine, the shaft belt motor and the electric motor.