The direct metallurgical bonding of C45 steel/tin-lead alloy bimetallic structures was achieved by the hybrid TIG arc and droplet deposition manufacturing. The microstructure, interface element distribution and main phases of the steel/lead bimetallic structure were studied by metallurgical microscopy, scanning electron microscopy and X-ray diffraction. The results indicated that the steel/lead bimetallic structure interface formed by the droplet deposition composite TIG arc additive manufacturing process are no obvious cracks, pores and other macroscopic metallurgical defects; According to the distribution of intermetallic compounds (IMCs) at the steel/lead interface, there is both "reactive wetting" and "inert wetting" during the impact and spreading of lead alloy droplets on the C45 steel substrate, where the reactive wetting interface has small fluctuations and the IMCs at the interface are FeSb₂ and FeSn₂, and the inert wetting interface does not precipitate reaction products and has tiny pore defects. The IMCs layer thickness at the center of the molten pool is the largest, and the IMCs layer thickness is about 6 μm. The IMCs layer thickness at the interface shows a non-linear decreasing trend as the test position gradually moves away from the center of the molten pool.