Interleukin-22 (IL-22) , a member of the IL-10 cytokine family, is secreted by a variety of immune cells. Its receptor (IL-22R) is mainly expressed in non-hematopoietic endothelial cells and stromal cells. IL-22 plays important roles in mucosal barrier defense, tissue repair, epithelial cell survival and proliferation by binding to its receptor. The expression of IL-22 is closely associated with various metabolic diseases, and has become a hot topic in the field of metabolism in recent years. This article reviews the research progress of IL-22 in fatty liver disease, obesity, diabetes and other chronic metabolic diseases.