Abstract: As a crucial bulk chemical and a liquid hydrogen carrier in the energy sector, ammonia exhibits dual attributes as both a “raw material” and a “fuel”, which bridges traditional chemical industries with new energy sectors. Leveraging ammonia’s superior energy characteristics and China’s strategic needs for energy security, it enables a full-chain “zero-carbon” green energy cycle featuring “renewable power-to-hydrogen—ammonia-based hydrogen storage—safe and low-cost ammonia transport—zero-carbon hydrogen production and utilization.” As a green liquid hydrogen carrier and fuel, ammonia holds significant potential in energy end-use applications such as industrial hydrogen production/refueling, fuel cells, engines, and industrial boilers/kilns. To advance green ammonia-hydrogen energy applications, critical challenges must be addressed, including the high reaction temperatures of existing ammonia decomposition catalysts, bulky and energy-intensive ammonia decomposition reactors, and the complex processes and inefficient component matching in ammonia-hydrogen conversion equipment. A systematic approach is urgently needed to design and develop ammonia decomposition catalysts and reactors, followed by the development of a series of ammonia-hydrogen energy equipment （e.g., ammonia-to-hydrogen systems, ammonia fuel cells, ammonia internal combustion engines） and integrated conversion and utilization solutions. First, the synergistic enhancement of catalyst efficiency and long-term stability achieved through multi-dimensional strategies is reviewed. Second, an analysis of industrial challenges and technological advancements in ammonia decomposition reactors is followed. Then, application cases developed through deep industry-university-research collaboration are highlighted, which include industrial-scale ammonia-to-hydrogen and refueling stations, ammonia fuel cell power generation, ammonia-hydrogen thermal engine power generation, and ammonia-hydrogen co-firing equipment. Finally, future prospects for ammonia-hydrogen energy technologies and industrial applications emphasize the urgent need to improve the activity and stability of ammonia decomposition catalysts, develop efficient and compact ammonia-to-hydrogen reactor devices aligned with the kinetic properties of the catalysts, and optimize the multi-component synergistic matching and process control design of ammonia-hydrogen energy equipment.