Abstract: For tubular workpiece surface deposited by Cu, the process of deposition by automatic plasma welding with melting strip electrode was designed and researched.The Cu strip electrode enters the welding region with the passive automatic feed-in manner. The plasma arc burns between the tungsten, and copper strip and the protective agent is blown into the welding region.The plasma arc makes the copper strip melt, and the Cu deposited layer was formed on the base metal surface of steel.The welding process is stable and the weld appearance is excellent.The detected results show that the deposited layer of of pure copper with 1 -6 mm thickness can be gotten.The pure copper and the base metal can be welded together without the base metal being molten.The shear strength exceeds 150MPa, which is greater than the strength of Cu layer.The bonding quality is excellent and there is no welding defects such as gas pore, incomplete fusion and slag inclusion.The SEM and EDAX results show that metallurgical bonding by diffusion is formed between the deposited pure copper layer and the base metal.And within the distance of 10 -30 μm from the side of the deposited copper layer interface, the content of Fe decreases to less than 1%.