Polysaccharides are high molecular weight compounds composed of multiple monosaccharide units connected by glycosidic bonds. They are a type of carbohydrates that are widely found in plants, animals, and microorganisms and have a variety of biological functions and applications. Polysaccharides and their derivatives have a variety of biological activities such as anti-tumor, anti-inflammatory, antiviral, and hypoglycemic, and are widely used in drug research and development, and also have potential applications in food materials.