Abstract: The production level of duplex stainless steels in Europe and USA is described from the aspects of standards, the chemical components and properties of 10 lean duplex stainless steels listed in ASTM are analyzed, the historical standard making process of each lean duplex stainless steel in the standards of bar, plate and pipe materials in USA is summed up, and the key technology of research & development of lean duplex stainless steels and their tubular products is pointed out. Analysis indicates that the new type lean duplex stainless steels, typically S32101, are developed rapidly in Europe and USA in recent years, and, as new grades of seamless and/or welded pipes, are listed in the standards of stainless steel pipe in USA. S8XXXX series steels are already added in the stainless steel tandards in USA, therefore the research & development of lean duplex stainless steels and their tubular products should be speeded up in China.