Abstract: Aiming at that the lining layer of 0.6 mm + 4.0 mm thin-lined 304/Q235B composite pipe cannot be welded alone, the two-layer three-pass welding method of transition layer+base layer (divided into filling layer and cover layer) and tungsten inert gas welding (TIG) were proposed. The ER309L welding wire, argon-free welding wire TGF309L and nickel-based alloy welding wire ERNiCrMo-3 were used to weld the transition layer. The ER70S-6 welding wire was used to weld the filling layer and the cover layer. Moreover, three welding schemes were designed and the microstructure and corrosion resistance of the welded joints were analyzed. The influence of the selection of welding materials with different transition layers on the corrosion resistance of welded joints was emphatically analyzed, the results show that the welds of the three welding schemes are well formed. The transition layer welds with ER309L and TGF309L welding wires are austenite and a small amount of wormlike ferrite. The transition layer welds with ERNiCrMo-3 welding wire are composed of fine nickel-rich austenite equiaxed grains and intercrystalline structures. The self-corrosion current of the welded joint with ER309L and TGF309L welding wire is low, while the length of passivation region and breakdown potential of the joint with ERNiCrMo-3 welding wire are higher, and the corrosion resistance of the three schemes is stronger than that of the base metal of the composite pipe.