The invention relates to the technical field of a cold welding machine, in particular to a gas-protection precision cold welding system with an intermittent demagnetizing cooling device. the gas-protection precision cold welding system comprises a cooling piston cylinder, a magnetic cold core, a magnetic cold core driving coil group, a cold end piston and a hot end piston, wherein the cooling piston cylinder is a cylindrical ceramic tube, and a cold exhaust hole, an air inlet hole and a hot exhaust hole are formed in the side face of the cooling piston cylinder from left to right in order; themagnetic cold core is a loose and porous paramagnetic material cylinder and is arranged at the center of the cooling piston cylinder, and the magnetic cold core driving coil group is twined on the area, corresponding to the magnetic cold core, of the outer side of the middle segment of the cooling piston cylinder; and the cold end piston is arranged on the left side of the cooling piston cylinder, and the hot end piston is arranged on the right side of the cooling piston cylinder. As a design of protecting-gas magnetic refrigeration is added, under the condition of refrigeration without adding a liquid channel and adopting a compressor, the gas-protection precision cold welding system realizes constant-temperature control for precision cold welding workpieces and improves the consistencyof welding quality of precision cold welding.