Abstract: In view of the questions that impact-resisting performance of the domestically produced hard alloy welding rod used in strengthening the steel tooth roller cone bits tooth face is bad,and wear-resisting performance is insufficient,many tests and theorectic analysis is made on the samples which make of 20Ni₄Mo which is used to make body of the steel tooth roller cone bit in the article,and select the hard alloy and the diamond possessing the good wear-resisting performance as the material which strengthened the tooth face,complete the superficial strengthening study of steel tooth roller cone bit by adopting the composite welding technology,enhance the wear-resisting and the anti-attacks abilities of the 20Ni₄Mo surface.Through simulating working conditions of the steel tooth roller cone bit,examine wear-resisting performance of the substrate material surfaces welding layer by the impact abrasion test,an new effective way to strengthen the surface of the steel tooth roller cone bit is set up.