The air separation industry is mainly divided into two major areas: air separation unit and industrial gas. Overall, in terms of the development of large-scale air separation units in China, the absolute majority of the unit in the world is produced by China, and the 60,000-grade air separation units account for over 75% of all air separation units in the world; the 100,000-grade single unit is produced domestically, and the super-huge air separation unit is mostly needed in the market in recent three years. With the rapid development of modern science and technology, the trends of air separation units will be: firstly, large-scale and clustering; secondly, gradual domestication of core technologies; thirdly, refinement, i.e., developing efficient energy-saving technologies for different applications; fourthly, highly automatic and intelligent.