Sialoadhesin (Siglec-1 or CD169) is a sialic acid-binding Ig-like lectin expressed selectively on macrophage subsets. In inflammatory response, Siglec-1 can modulate the secretion of MIP-1 alpha/beta, MCP-1, MIP-2 and other cytokines, and promote the occurrence of inflammatory reaction. During viral infection, Siglec-1 can promote the infection and phagocytosis of virus by mediating the binding of pathogens and macrophages. In the regulation of immunity, Siglec-1 can regulate innate immunity and adaptive immunity, by inhibiting the excessive expression of IFN-α and the activation of DC cells. This review mainly focuses on the new advances of research on Siglec-1 in pathogen infections, inflammation and immunoregulation.