Abstract: The effect of filler wire composition on the mechanical properties of filler wire and weld metal was studied. The results show that when, Ti,Mn and Nb contents increased in the filler wire, the tensile strength and hardness of the filler wire and weld metal increased. The impact energy of the weld metal increased with the increase of Al, Ti and Nb contents in the filler wire. But when Mn content increased in the filler wire, the impact energy of the weld metal decreased. By adjusting the composition of the filler wire,the weld metal could meet the requirements for the key components of nuclear power plant.