Abstract: Functional plant polysaccharides are macromolecular carbohydrates produced by the metabolism of plant cells, which are macromolecular carbohydrates formed by the polymerization of more than 10, or hundreds or even thousands of monosaccharide molecules through glycosidic bonds; It has a variety of biological activities such as blood lipids, immune regulation, anti-tumor, and intestinal microecology regulation. It also has the advantages of wide sources, safety and non-toxicity, high activity, and high environmental affinity. It has broad application prospects in the field of food and biomedicine. This paper mainly reviews the relevant research progress of plant polysaccharides in terms of structure analysis, extraction methods, immunomodulation, anti-tumor, antioxidant, anti-aging, hypoglycemic and hypolipidemic activities and their application as functional factors, in order to provide reference and reference for scholars' research and further development and utilization.