Dendritic cells (DCs) are known to be the most powerful professional antigen presenting cells so far. It could not only initiate primary immune response, but down-regulate immune reaction as well (1). DCs play an important role in maintaining immune homeostasis for their distinguished immune regulatory capability. Also, DCs are initial factors in auto-immune diseases, and play a key role in immune escape of pathogens and tumors. It is known that immune regulatory capability of DCs is closely related to pattern recognition and immune regulation of the receptors on DC surface. Among those receptors, C-type lectin receptors (CLR) and Toll-like receptors (TLRs) have been sufficiently studied. As a member of CLR family, DC-SIGN (DC-specific ICAM-grabbing non-intergrin) is important in immune regulation of DC. DC-SIGN is also denoted as CD209, which was first discovered by American experts who were studying human immunodeficiency viruses (HIV) in 2000 (2). As DC-SIGN could bind to gp120, promote CD4+ T cell infection by DCs and thus results in immunodeficiency, it is also denoted as HIV-1 gp120 binding C-type lectin (2, 3). Because such C-type lectin mediates DC binding to ICAM-3 on T cell surface without intergrin, but with Ca2+ participating, it is denoted as DC-SIGN. Recent studies show that DC-SIGN is the pattern recognition receptor and adhesion receptor of DCs, and plays an important role in DC migration and adhesion, inflammatory response, activating T cells, initiating immune response and immune escape of pathogens and tumors. Also, DC-SIGN is found to participate in DC regulation of natural immunity and adaptive immunity (2, 3). Our review focuses on functions of DC-SIGN in immunoregulation.