The work aims to modify the residual stress of VPTIG welded 2219 aluminum alloy joints by cold spraying. Cu coating was prepared on the 8 mm thick VPTIG welded 2219 aluminum alloy joint surface by cold spraying (CS) technology. The microstructure, mechanical property and residual stress changes of joints before and after CS were analyzed. The modification effect on the residual stress of joints and its mechanism caused by "shot peening effect" of high-speed colliding particles and "heating effect" of hot gas in CS were explored. There was no significant change in the microstructure of the joint before and after CS. However, the obvious plastic deformation was observed on the joint surface (i. e. the interface between Cu coating and joint fusion zone). After spraying, the microhardness of near-top surface of the weld zone was increased, and the influence depth was about 2 mm (at the weld toe). The tensile strength of the coated joint was slightly reduced, which was caused by the localized change of tensile strain of the joint under the constraint of Cu coating. However, there was no significant change of joint tensile strength after "shot peening effect" or "heating effect" treatment. All specimens fractured along the fusion zone initiating at the weld toe. The distribution of residual stress in welded joints was generally tensile stress, with the maximum at the weld joint. After cold spraying, the residual peak stress of the joint was decreased from about 200 MPa to about 24 MPa, and the stress in most regions of the joint changed from tensile stress to compressive stress, and was distributed more uniformly. Therefore, CS can improve the residual stress of VPTIG welded 2219 joints significantly. The "shot peening effect" of particles can remarkably improve the residual stress of the joint. Although the "heating effect" of high-temperature gas flow cannot significantly reduce the residual stress, the residual stress distribution becomes more uniform.