Abstract: This paper briefly introduces the statusof the application of GMAW process, and the requirements of national nuclear safety regulation for process applications. This paper analyzes the difficulties of GMAW welding process application from the aspects of the support from the design organizations for steel containment vessel, the determination of welding groove form and size, welding parameters matching, groove on the back and clear root and other automatic GMAW welding process. This paper introduces the preparation before technology application from the aspects such as welding methods, equipment, material selection, welding process matching test and welding procedure qualification. Finally, this paper introduces the automatic GMAW welding application requirements and implementation results. The application results show that the GMAW welding process in the plant steel containment vessel welding is feasible.