Aiming at the disadvantages of the present techniques for repairing the damages of aluminum-alloy aircraft structure, laser welding technique was proposed for repairing the damages of 2A12 alloy structure. Laser welding neck of Al-5Mg-0.3Sc alloy and 2A12 alloy was investigated. Through metallographic microscope and scanning electronic microscope, the properties such as metallurgical structure, tensile strength of the welding seam and the matrix alloy, tensile strength contrast to rivet specimen were studied. The experimental results show that the grain of the welded joint between 2A12 and Al-5Mg-0.3Sc is obviously refined, and tensile strengths of welded joint and riveted structure of 2A12 are equivalent. Laser welding neck structure of Al-5Mg-0.3Sc alloy and 2A12 can replace riveted repair structure of 2A12.