Abstract: The low-temperature brittle fracture of steel is a major challenge in steel structure engineering, which threatens the safety of structures in low-temperature environments. Cryogenic steel is widely used in various liquid gas storage tanks, pipelines and equipment serving in low-temperature environments because of its good low-temperature toughness and low toughness-brittle transition temperature. For better understanding its performance characteristics, brittleness mechanism and product development of the cryogenic steel, a review of research progress available in the literature is conducted herein. First, the concept and regulations of cryogenic steel were introduced in this paper. Then, four main theories about toughness-brittle transition were summarized, namely classical mechanics theory, lattice dislocation theory, energy theory and statistical theory. Based on the lattice dislocation theory, the micro mechanism of the change in steel properties at low temperatures was explained in detail, the main influencing factors of toughness-brittle transition, and the toughening mechanism and measures of steel at low temperatures were analysed, and the main ideas of research and development of the cryogenic steel were clarified. Finally, the current general classification and product series of cryogenic steel were introduced herein. At present, the research and development of the cryogenic steel are mainly focused on Ni-containing cryogenic steel and high-manganese austenitic cryogenic steel. The chemical composition content and performance requirements of different content Ni-containing cryogenic steel in domestic and foreign standards were compared, and the types of cryogenic steel commonly used in the field of containers in China were summarized. Combined with the Antarctic Projects, an idea was put forward for the use of cryogenic steel in building structures in China to further promote the application of cryogenic steel materials and structures.