Abstract: This invention relates to a composite mandrel and its processing technology, including: processing, connection, welding, alloy overlaying, tempering after overlaying, polishing, chrome plating etc., on the whole and auxiliary body of mandrel. The composite mandrel includes a plurality of main and auxiliary bodies, the surface is overlaid with high temperature resistant, wear resistant, thermal fatigue resistant alloy, polished, and chrome plated, obtaining the characteristics of wear resistance, thermal fatigue resistance and high temperature resistance. The whole process not only increase the strength, toughness and hardness of the mandrel, improves its service quality, but also prolong the service life. With simple structure and reliable quality, composite mandrel can meet the requirements of different running condition.