As a sustainable resource, hydrogen is considered to be a competitive candidate for future energy consumption. Ammonia is a promising carbon-free hydrogen carrier with a hydrogen content of 17. 6wt%. Ammonia decomposition is low-cost and high-efficiency, and on-site ammonia decomposition can to a certain extent serve as a route to hydrogen storage and transportation. Various metal-based ammonia decomposition catalysts have been developed, and ruthenium-based catalysts are superior due to their suitable Ru-N binding energy. In recent years, people have been working to improve the performance of Ru-based catalysts by studying various support and promoter materials. Advanced technology is used to reveal the relationship between catalytic performance and catalyst microstructure to reduce the loading of Ru and the reaction temperature to improve its economicity. This paper describes the different ways to produce hydrogen and summarizes the economics of green ammonia and the construction of green ammonia projects by domestic and international companies. Meanwhile, the mechanism, and kinetic and thermodynamic processes of ammonia decomposition reaction are analyzed. The research progress of noble metal Ru-based catalysts for ammonia decomposition and the effects of different types of carriers and promoters on the catalytic performance of Ru-based catalysts are reviewed. In addition, the ammonia decomposition reactor and its aging issues are introduced. Finally, the improvement measures and future development direction of ammonia decomposition catalytic hydrogen production are prospected, aiming to provide supporting information for the development of‘hydrogen-ammonia’energy. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.