Automobile gear laser welding is a development trend. At present, the world's automobile manufacturers have used the laser welding gear to replace traditional welding methods, such as ERW (electric resistance welding), induction welding and EBM (electron beam welding). The laser gear welding can work in non-vacuum. Without welding deformation,the gear has no need to be further processed after welding. In addition, the welding joints have general mechanical performance that is equivalent or superior to base metals, which ensures the larger torque transmission of gears.