Abstract: Principle of non-electric welding technology was described briefly. It was introduced from three key problems of burning process of non-electric welding pen, separation and protection of slag, and weld alloy and interface strengthening between weld metal and welding base metal. Combined with optimization and application of non-electric welding technology at present, current research progress of non-electric welding technology was summarized, and problems faced by non-electric welding technology were analyzed and its prospect was prospected. In the research of the core problem of non-electric welding technology, that was burning process of non-electric welding pen, formula of welding pen with Al/oxide exothermic system as heat source has been formed. On this basis, the author’s group has successfully introduced Al/sulfate exothermic system to increase heat input of non-electric welding, which provided theoretical basis and technical support for further expanding application field of non-electric welding technology.