Abstract: The G520 precipitation hardening stainless steel was welded with metallic flux-cored wires with Cr content of 10 wt.%, 18 wt.%, 26 wt.%, and 34 wt.% respectively.The effect of Cr content in flux-cored wire on the microstructure and mechanical properties of G520 precipitation hardening stainless steel welded joints was studied.The results show that the microstructures of the weld zone of the four groups of welded joints are all austenite and δ-ferrite, and with the increase of the Cr content in the flux-cored wire, the δ-ferrite changes from a point block to a network and a strip.The combined effects of the content of Cr, the content of δ-ferrite and Cr₂₃C₆, and the average size of austenite grains in the microstructure affects the tensile properties and room temperature impact toughness of welded joints.When the Cr content in the welding wire is 26 wt.%, the Mechanical Properties of the G520 precipitation hardening stainless steel welded joint is the best, the tensile strength is 969 MPa, the elongation is 20.8%, the impact energy is 60.7 J.