Abstract: 20Mn23Al non-magnetic steel plates with thickness of 12 mm were welded by inert gas tungsten shielded welding-gas metal arc welding (TIG-GMAW), inert gas tungsten shielded welding-shielded metal arc welding (TIG-SMAW) and inert gas tungsten shielded welding-submerged arc welding (TIG-SAW), respectively. The microstructure and properties of welded joints by different welding processes were studied. The results show that the microstructures of the weld in welded joints all consisted of austenite, δ ferrite and carbides by three welding processes. The grain size of TIG-SAW joint was larger than that of the other two welded joints. The hardness of the weld in TIG-SMAW joint was the highest, then TIG-GMAW joint, TIG-SAW joint in turn. The impact toughness of TIG-GMAW joint was the best, then TIG-SMAW joint, TIG-SAW joint in turn. The impact fracture of TIG-GMAW joint and TIG-SMAW joint had a characteristic of ductile fracture, while TIG-SAW joint had a mixed fracture characteristic of toughness and quasi-cleavage. The corrosion resistance of TIG-SMAW joint was the best, then TIG-GMAW joint, TIG-SAW joint in turn.