Type 2 diabetes mellitus (T2DM),with complex and unintelligible pathogenesis,is mainly characterized by persistent high levels of blood glucose.Studies have demonstrated that the disorder of the gut microbiota will lead to a decrease of short-chain fatty acids,affect the metabolism of bile acids,branched-chain amino acids and lipopolysaccharide secretion,so as to induce insulin resistance and chronic inflammation and gradually develop into T2DM.Polysaccharides,which have a positive regulatory effect on the intestinal microecology,are polymer compounds made up of more than ten monosaccharides connected by glycosidic bonds.They can improve the function of gut microbiota,maintain the balance of gut microbiota,and improve a series of metabolic disorders caused by intestinal flora disorders in T2DM,thus reducing insulin resistance and achieving glycemic control.This article reviews the influence of gut microbiota on T2DM and the effect of polysaccharide-gut microbiota interaction on type 2 diabetes mellitus,so as to provide new ideas for the treatment of T2DM with polysaccharides.