At present, the domestic medium voltage ring main unit usually adopts two processes: laser welding and MIG/MAG welding. Because laser welding has higher requirements for the previous process (plate preparation, splicing, etc.), the equipment investment is relatively large, which has become a limitation of laser welding. As an important factor for the further promotion and application of medium voltage ring network cabinets, laser welding technology, which has a high adaptability to the accuracy of sheet metal splicing, has become a hot technology for research and promotion.