Abstract: The precipitations of plasma welded joints were analyzed at CCT digram from Jmatpro software. PAW welding of AL-6XN was carried out to study the mechanical properties, microstructure, corrosion resistance and composition distribution.Resultsshowed the tensile strength of PAW joint was equal to that of GTAW welding joint; that the pitting corrosion rate of the plasma welded joint was as high as 70 mg/(dm²·d), mainly concentrated near the fusion line; that Ni, Mo and other elements in the joint were severely segregated, particularly near the fusion line; that the solution treatment could eliminate elemental segregation of the plasma welded joint and restore the corrosion resistance of the joint.