Human milk is a natural nourishing agent for infants and young children, which plays a crucial role in promoting growth and development, and contains a variety of prebiotics that are not found in cow milk. There are two main types of carbohydrates in human milk: lactose and human milk oligosaccharides (HMOs). HMOs are the third most abundant components of human milk after lactose and lipids. HMOs are complex mixtures of more than 200 non-digestible and non-nutritive carbohydrates, which have the main functions of maintaining intestinal microecological balance, regulating immunity, preventing necrotizing enterocolitis, promoting brain development and reducing infection. 2'-fucosyllactose (2'-FL), 3-fucosyllactose (3-FL), difucosyllactose (DFL), lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT), 3'-sialyllactose (3'-SL), and 6'-sialyllactose (6'-SL) are the most abundant components in HMOs. DSM, Chr. Hansen, DuPont and other multinational corporations have deployed this area for years. Many Chinese companies also joined in, as well as the academic institutions. These events will together drive the development of HMOs industry.