Abstract: Interleukin 35 (IL-35) is a new member of IL-12 family. Its structure is similar to that of other members (IL-12, IL-23 and IL-27), which is composed of two subunits, p35 and EBI3. IL-35 takes anti-inflammatory and immunosuppression effects mainly through STAT1 or STAT4 signaling pathway, and plays an important role in a variety of autoimmune diseases, such as rheumatoid arthritis, experimental autoimmune encephalomyelitis, type 1 diabetes and so on.