As one of the most important nuclear power standards,mechanical component standard of nuclear island is an important safeguard for nuclear power construction. At present,the coexistence of the two sets of mechanical component standards has brought unnecessary duplication and waste to the design and manufacture of mechanical components of nuclear islands. Among them,the differences between the two sets of welding material standards,the causes of the differences and the main difficulties in solving the differences are analyzed,and the solutions are given. Finally, the current work progress is introduced. The pioneering work on technical route unification of welding material standards has great practical significance for improving the standard system of nuclear power in China, promoting independence of the standard and facilitating the "go global" of China’s nuclear power.