Abstract: Hydrogen energy is widely used in various industrial fields as a zero-carbon secondary energy source. As a hydrogen storage carrier, ammonia has the advantages of high hydrogen storage capacity (17.6 wt%), high energy density and easy liquefaction, and its decomposition products are only hydrogen and nitrogen, which is in line with the national strategic development direction of “carbon peak, carbon neutrality”. However, the activation energy of ammonia decomposition is high and the reaction conditions are harsh. Therefore, the development of safe, efficient and cheap ammonia decomposition hydrogen production technology is crucial for the development of hydrogen energy. In this paper, the basic principle of ammonia decomposition reaction is explained, and the research work of NH₃ decomposition to hydrogen production catalyzed by various metal catalysts is introduced. Fe, Co and Ni based catalysts show higher NH₃ decomposition activity because of their moderate metal-nitrogen binding energy. Beginning from the regulation of active metal centers, the researchers designed to improve the activity of ammonia decomposition by adding secondary metals, regulating morphology, defects/doping, constructing metal-carrier interactions, etc. The many characterization methods were used to reveal the structure-activity relationship of catalysts. In addition to the iron series catalysts, this paper also focuses on the plasma technology to improve the efficiency of ammonia decomposition and reveals the principle, types, mechanism of plasma and the synergistic effect in auxiliary catalytic ammonia hydrogen production. In this paper, the latest work in the design of ammonia decomposition catalyst for hydrogen production is introduced and the strategies for improving NH₃ decomposition for hydrogen generation are summarized. The advantages of plasma-assisted NH₃ decomposition are emphasized. This paper has certain reference value for the development and application of ammonia decomposition hydrogen generation catalysts, in order to provide a new idea for the development of ammonia hydrogen production technology and industrial application in the future.