Apoptosis inhibitor of macrophage (AIM), belongs to the group B of scavenger receptor cysteine rich-super family (SRCR-SF). AIM is a soluble protein secreted by macrophages. The expression of this protein is controlled by the liver X receptor (LXR), and it plays an important role in the immune response of the body. AIM, as a secreted protein of macrophages, plays a broad role. It not only inhibits the apoptosis of macrophages, but also participates in the regulation of macrophage polarization. In addition, relevant studies have revealed that AIM is involved in various physiological and pathological processes such as inflammation, obesity, atherosclerosis and cancer; It was used as a biological diagnosis marker for diseases such as tuberculosis, liver cirrhosis and the like; Besides, it can promote lipolysis of adipose cells by inhibiting the activity of fatty acid synthase (FAS), playing an important role in the regulation of lipid homeostasis, lipid metabolism and autoimmune diseases. In this paper, we reviewed the molecular characteristics of AIM and its effects on inflammation, lipid metabolism and other related diseases, showing multiple functional characteristics of AIM to provide the basis for relevant medical research.