This paper presents a new method of postweld treatment. The 5154 aluminum alloy was cleaned by Nd:YAG laser after welding. The surface morphology, energy spectrum, friction and wear properties, hardness, and residual stress of the welded joint at different cleaning speeds were studied. The results show that an Nd:YAG laser can effectively remove the welding slag and eliminate the pores in the weld under a certain cleaning speed. When the cleaning speed is in the range of 5.2-20.7 mm/s, laser cleaning can improve the heat-affected zone's tribological characteristics. Laser cleaning can eliminate the residual stress of the welded joint and improve the welding joint's strength, which provides a reference for laser cleaning instead of traditional heat treatment.