Abstract: The deflect of ZG14Ni3CrMoV cast steel was repair welded with 0CrNi3MoV as electrode, and then the steel received quenching and tempering treatment. Stresses of the steel before and after the repair welding as well as the mechanical properties were tested. The results show that it is feasible to repair weld ZG14Ni3CrMoV cast steel with 0CrNi3MoV electrodes and then give it a quenching and tempering treatment. Welding residual stress has improved obviously and the residual stress has changed from tensile stress to compressive stress; the strong toughnesses in the weld area and the base metal are similar and the hardness of the joint is even.