Abstract: The two-step metal oxide thermochemical cycle hydrogen production technology is a clean hydrogen production method that utilizes a high-temperature heat source to drive the oxidation-reduction reaction of metal oxides to achieve water splitting. This technology involves two steps: first, at high temperatures （1000−1500 ℃）, metal oxides undergo thermal splitting in an inert atmosphere to release oxygen and form low-valent oxides. Then, at moderate to low temperatures （500−800 ℃）, the low-valent oxides react with water to produce hydrogen and revert to their initial form. This two-step cycle enables efficient, high-purity hydrogen production. Compared to direct thermal hydrolysis, its core advantages lie in its strong temperature adaptability, enabling deep integration with zero-carbon heat sources such as solar and nuclear energy; hydrogen and oxygen are produced in separate steps, allowing hydrogen to achieve high purity without separation; and metal oxides, as oxygen carriers, can be reused, providing an important pathway for large-scale clean hydrogen production. Based on this, a systematic review of the research progress of this technology is presented, with detailed introductions to three representative reaction systems: single metal oxides, composite metal oxides, and synergistic reduction with the introduction of a reducing medium. The selection and structural design of metal oxide materials, reaction temperature and atmosphere control, reaction kinetics and mass transfer process optimization, catalyst and additive selection, as well as system design and process integration. Strategies to enhance hydrogen production efficiency and stability under each reaction system are summarized, and challenges such as high-temperature sintering, slow reaction kinetics, and high system costs are identified as key obstacles to further technological development. Future research could focus on developing new high-efficiency oxygen carriers, regulating oxygen vacancy concentration to further reduce reaction temperature; innovative reactor structure design to enhance efficiency; and constructing multi-heat source coupled intelligent control systems, among other areas, to advance the two-step metal oxide thermochemical cycle hydrogen production technology toward large-scale, low-cost development. As the“dual carbon”goals continue to advance, this technology is expected to provide an effective and feasible pathway for energy structure transformation and green, low-carbon development.