By analyzing the welding technology problems in the installation and construction of nuclear power plants,a cantilever automatic welding technology scheme is proposed to improve the pipeline prefabrication efficiency and ensure the welding quality. The feasibility of the scheme is demonstrated from the aspects of welding cost,welding efficiency,welding quality and welding safety. The results show that the cantilever automatic welding technology has higher superiority than manual welding technology,and it is completely feasible.