Firstly, said invention utilizes nitridation method to form iron nitrogen compound or iron nitrogen compound containing carbon on the oil pipe collar thread surface, its technological process includes the steps of degreasing collar surface, water-washing, drying, external surface protection, gas nitridation and cooling; then utilizes phosphatization method to form uniform phosphated layer on collar thread surface, its technological process includes the steps of degreasing surface, water-washing, weak corrosion, water-washing, surface activation, phosphatization treatment, water-washing, drying and soaking in oil. The obtain thread surface has stronger resistance to thread galling.