Abstract:The seaweed resources are extremely abundant in China, but currently it is mainly used in a few areas, such as food, feed and health goods manufacture. Hence, the high-value utilization of seaweed resources needs to be further developed. Algal polysaccharides are important components of seaweed cell wall and possess various biological activities. However, it is difficult to be absorbed and utilized by the body due to its high polymerization, high viscosity and poor solubility. Algal polysaccharides can be degraded into oligosaccharides through physical, chemical and biological methods, resulting in significantly increased solubility and physiological activity, which makes them suitable for use in a variety of fields including food, health goods, feed and agriculture. The development of green preparation technology of algal oligosaccharides based on enzymatic process has superior advantages over traditional methods in terms of efficiency, cost and pollution. This paper reviews the research progress on the physiological activities and enzymatic conversion of marine oligosaccharides, such as alginate oligosaccharides, agar oligosaccharides, carrageenan oligosaccharides and fucoidan oligosaccharides, which could provide the basis for the high-value utilization of seaweed resources.