Retinol-binding protein (RBP) is a carrier transporting retinol (vitamin A), and is an important member of lipocalin family which can bind small hydrophobic substances. The studies of structure and function of RBP are given much attention by scientists. The progress in properties and structure of RBP is summarized, and the binding sites and structural feature of the interaction of RBP with transthyretin and receptor are discussed.