Abstract: The influences of post-weld heat treatment on microstructure and mechanical properties of manual SHS welding at different temperatures are studied.The results indicate that the diffusion activation ability of elements can be reached when the annealing temperature is more than 300℃.With the increasing of temperature,the tensile strength and the impact toughness of the welded joint improve,the micro-hardness gaps near the fusion line of the base metal and the welded alloy reduce,and the microstructures in the fusion area distribute uniformly.Through spread scanning of the element by the EDS energy spectrum,the concentration change of the major elements in the fusion area is found out,which is from mutation form before the post-weld heat treatment into gradient form and strengthens the intensity of the fusion zone.