X-ray diffraction approach is used to test the residual stress of the surface of the linear friction welding of titanium-alloy. It is proved that the residual stress in X and Y direction in the center of the welding is tension stress

and the stress in Y direction is obviously stronger than that in X direction. The stress in the heat affects zone of the welding is compressive stress

and the value of stress tends to zero from the center of the welding to the out zone. The stress values decrease to varying degrees in all regions of specimen after vacuum heat treatment. Overall

the residual stress of the surface tends to uniformity after heat treatment.