n order to achieve the goals of "Carbon Peak" and "Carbon Neutrality", green and low-carbon has become an important theme in the development of the iron and steel industry. As a clean energy with diverse sources, clean and low-carbon, flexibility and efficiency, and rich application scenarios, hydrogen energy has been included in the national energy strategic deployment of many countries. Hydrogen metallurgy can realize steel production without fossil energy smelting, which is the most important way to achieve zero carbon emission, and has become a hot spot in the current research of the global iron and steel industry. In recent years, some major steel companies at home and abroad have increased technology R & D and project investment in the field of hydrogen metallurgy according to their national conditions, followed by slight differences in technical routes. At present, the hydrogen metallurgy technology route mainly includes three kinds including blast furnace hydrogen smelting technology of "hydrogen instead of carbon", hydrogen-based direct reduction process of obtaining solid reduced iron by hydrogen rich or total hydrogen as reducing agent, and hydrogen-based melting reduction process of producing molten iron with hydrogen-rich or pure hydrogen gas as reducing agent. The process research and development, implementation progress, application status and technical challenges of the three hydrogen metallurgy technology routes are introduced with positive significance for reducing carbon emissions in the iron and steel industry. At present, hydrogen metallurgy still faces severe challenges in terms of cost, capital, technology and policy in the process of realization, the policy support is the basis for the expansion of hydrogen application scale, and the breakthrough of hydrogen metallurgy technology is the key to the large-scale application of hydrogen energy in the iron and steel industry.