Human milk oligosaccharides （HMOs） are a group of complex glycans in human milk and play an important role in promoting the growth and development of infants, and more than 200 kinds of HMOs have been identified so far. In this paper, the types and structures of HMOs and their roles in improving infant intestinal health, promoting immune system development and brain development were reviewed. The application status of HMOs was summarized, the possibility and necessity of industrial production and application of HMOs in the future were prospected.