Abstract: Arc characteristics of hollow tungsten arc in the atmospheric environment and low vacuum environment and its welding characteristics were briefly introduced. Technical characteristics and research status of hollow tungsten coaxial laser hybrid welding,coaxial electron beam hybrid welding,and coaxial wire filling welding were summarized. The unique technical characteristics of the organic integration between“high-efficiency welding”and“high-quality forming”of hollow tungsten coaxial wire filling welding were analyzed. The challenges faced by the engineering application of hollow tungsten arc welding were reviewed. It was pointed out that the progress of this technology would largely depend on researchers who could make breakthrough achievements on the following key scientific and technological issues,such as putting forward a new idea for the optimization design of hollow tungsten electrode welding gun from the perspective of arc stability and welding metallurgy,stable burning boundary conditions and control measures of welding arc in hollow tungsten and coaxial hybrid heat source,the coordinated control of welding wires’ stable melting and the droplet transfer process in hollow coaxial filler wire welding,phase transformation and microstructure evolution of the weld in the non-equilibrium solidification process.