Abstract: The 2205 duplex stainless steel pipe was welded by inert gas tungsten arc welding. The differences of chemical composition, microstructure, mechanical properties and corrosion resistance between the whole welding joint by ER2209 wire and the root welding joint by ER2594 wire were studied. The results show that compared with the whole welded joint by ER2209 welding wire, the chromium content in welded joint and heat affected zone of the root welding ER2594 welding wire was increased by 6%~10%, the austenite phase content was increased, the distribution of two-phase structure was more uniform, the mechanical properties and stress corrosion resistance were good, and the corrosion rate was reduced by about 95%, and the corrosion resistance of the root welding was better than the base metal. Therefore, using ER2594 wire for root welding could effectively solve the problem that the corrosion resistance of 2205 duplex stainless steel weld was worse than that of the base metal.