Abstract: Colitis is an inflammatory intestinal disease that lasts for a long time, has an unknown cause, and occurs repeatedly. It is usually accompanied by symptoms such as intestinal cell damage, intestinal immunity, and abnormal intestinal flora. Numerous studies have shown that dietary fiber, as a prebiotic, its metabolites can selectively improve the composition of the intestinal flora, which in turn improves the level of intestinal short-chain fatty acids, reduces the expression of inflammatory factors, and enhances the function of the intestinal immune barrier, thereby improving the inflammatory response of the organism. This anti-inflammatory effect of dietary fiber through its metabolites provides new research ideas to assist in the treatment of colitis. This paper outlines the pathogenesis of colitis, and the mechanism of interaction between dietary fiber and its metabolites with intestinal flora, inflammatory factors and immune cells, aiming to provide theoretical basis for the alleviation of colitis by dietary fiber and the development of functional foods.