The invention relates to a welding device, including a laser, a laser shaping assembly, a light beam motion control assembly, and a blowing assembly. The laser is used to emit laser beams. The laser shaping assembly is used to shape the laser beams into light spots. The light beam motion control assembly comprises an X-axis swinging lens, an X-axis swinging motor, a Y-axis swinging lens, a Y-axisswinging motor, and a control unit. The X-axis swinging motor is connected with the X-axis swinging lens. The Y-axis swinging motor is connected with the Y-axis swinging lens. The control unit respectively controls the X-axis swinging lens and the Y-axis swinging lens to move through the X-axis swinging motor and the Y-axis swinging motor, to change positions of the light spots illuminated on a workpiece, the light spots being reflected by the X-axis swinging lens and the Y-axis swinging lens, to weld the workpiece. The blowing assembly is used to blow shielding gas to the welding positions when welding the workpiece. The welding device can satisfy welding requirements of small size circular trace of a liquid injection hole.