Abstract: The life of plugs hardfaced by plasma transferred arc is about 3-5 times longer than that of the cast Cr17Ni2Mo stainless steel plugs. In this paper, the rationality, adaptability and reliability of the surfaced plugs are discussed through comparing the metallographs, high temperature hardness and chemical composition of the above two kinds of plugs, designing the structure of the hardfaced plugs and calculating the optimization of hardfacing layer thickness.