To research the effects of the pre-welding laser cleaning technology applied to the automobile plates coated with Al-Si covering, the Al-Si coating is cleaned firstly. And then the automobile plates are butt welded. Comparing with the tensile tests’ outcomes of welding the laser power P＝50 W, scanning speed S＝1～4 m/min, scanning times N＝2, which remains 20～21 μm coating thinckness. Meanwhile, the tensile strength of the welding line can satisfy 94% of the base metal, and as fast (4 min per component) as the efficiency could.