As people’s health awareness gradually increases, dietary nutrition has become a long-term discussion topic, and functional food has become one of the most concerned fields in the food and scientific industry nowadays. Among them, functional oligosaccharides are widely used in functional food as new green auxiliary materials or food additives. The concept and types of oligosaccharides are introduced, and the common preparation methods and physiological activities of functional oligosaccharides are reviewed, the application status of functional oligosaccharides is analyzed and summarized, the research and application direction of functional oligosaccharides are prospected, which has provided a certain reference for promoting the research and application of functional oligosaccharides.