Aiming at the problem of the residual tensile stress of aeronautical aluminum alloy parts after repair and processing, which affects the service life of components, a method based on low-energy input laser irradiation to reduce the surface residual stress of components is studied. The laser beam irradiates the concentration area of the residual stress,converting the elastic internal energy into plastic work by laser heating, resulting in the residual stress reduced. In order to verify the feasibility of this approach, four-point bending test was conducted on the 2A12 aluminum alloy sample, the residual stress was caused by the non-uniform plastic deformation during the bending. The laser radiating relieved the residual stress by scanning the stress concentration region. The surface residual stress of the sample was measured via X-ray diffraction. The results showed that the residual stress decreased significantly after laser scanning, and the tensile residual stress was completely eliminated. When the laser power was increased to 95 W, the compressive residual stress could be eliminated by around 77%. Through theoretical analysis and microscopic morphology comparison, it was found that no phase transformation occured before and after laser scanning. By analyzing the variation of the full width at half maximum for the diffraction peak of Al (311) crystalline plane, it was found that the laser heating decreased the dislocation density. With the increase of laser power, the decrease of dislocation density increases, which was one of the reasons for residual stress relaxation. Without changing the microstructure of the material, low-power laser irradiation could significantly reduce the surface residual stress distribution of the material.