Abstract: The ultra high strength steel 22MnB5 before and after quenching were joined by tungsten inert gas (TIG) arc welding,the mechanical properties and microstructure of welded joints were studied by experiments,and the corrosion property of welded joints was analysis and compare with the base metal as well. The result shows that the ferrite and pearlite of nonquenched material were transformed to martensite after quenching treatment. The welded joints of the base metal have good mechanical property and microstructures,the tensile strength and hardness of the joints are slightly lower than the one of the base metal,the tensile strength of welded joints of quenched material reach 1 179.59 MPa,that is slightly lower than that of quenched material,but much higher than that of non-quenched base metal. The corrosion rates were rising after quenching heat treatment, the corrosion rate of the welding zone is much higher than the base metal,and the welding zone corrosion rate of the quenching material is highest.