A welding test is conducted on nuclear grade hollow blade by robot automatic welding method,comparing with manual welding,the microstructure and microhardness distribution of the welded joint are analyzed,and the automatic welding parameters are optimized. The intelligent welding system of automatic welding is established,and the fixture of profiling structure is designed. The automatic welding production line is built with the linkage of multi-positioner,the trial production of hollow blade test piece is completed. Through the test, it is verified that the production efficiency of the system is twice higher than that of traditional manual welding. The welding position and segmented welding scheme of hollow blade are studied by welding numerical simulation analysis,and are compared with the actual blade welding. The results show that the deformation trend of automatic welding is basically consistent with the actual welding process,the weld is well formed.Through the research of hollow blade automatic welding system,the economy and reliability of nuclear power five stage hollow blade welding can be improved,and the product quality requirements can be better met. Thus the research has great practical significance in engineering application.