The invention discloses a stitch welding method of galvanized plates for an automobile. The two galvanized plates which are overlapped together and have a preset gap are subjected to stitch welding through a laser welding device, after arc extinguishing is started, decreasing of the power and speed of the laser welding device is matched with increasing of the defocusing amount, and arc extinguishing is completed. The welding speed and efficiency can be effectively improved, and the surface quality of weld seams is improved.