Functional plant polysaccharides are complex carbohydrate polymers with various biological activities and have positive effects on human health.However,natural polysaccharides are affected by high molecular weight,complex structure,poor uniformity and other factors,and direct consumption will limit the absorption and utilization of their biological activities in human body.Polysaccharide fermentation is a research field worthy of attention.Fermentation can improve the nutritional value and function of polysaccharides,and also contribute to the recycling of resources and environmental protection.In this paper,the effects of fermentation on the structure and bioactivity of polysaccharides were reviewed,so as to provide references for further effective utilization and product development of functional plant polysaccharides.