The soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) of rye bran were extracted by heat stable α-amylase， alkaline protease and glycosylase. The changes of polyphenol species and content before and after digestion of dietary fiber from rye bran， the changes of bioaccessibility after digestion and the changes of antioxidant activity during in vitro digestion were investigated to determine the components that can enter the gastrointestinal tract and be utilized by intestinal microorganisms. The results showed that the gallic acid in SDF and IDF increased significantly after gastrointestinal digestion (P<0.05)， and the SDF was 497% and the IDF was 1 771%. With the prolongation of digestion time， the release of polyphenols in SDF and IDF showed an increasing trend， which led to the gradual enhancement of antioxidant activity. The bioavailability of total phenols and total flavonoids of SDF was significantly higher than that of IDF (P<0.05)， and they reached 89.51% and 32.41% at the end of digestion. In summary， digestion is beneficial to promote the release of phenols and improve antioxidant properties six phenolic substances， namely ferulic acid， caffeic acid， chlorogenic acid， gallic acid， protocatechuic acid and kaferol may be used by gut microbes to regulate gut health. To provide theoretical support for SDF and IDF as food additives and improve the added value of rye bran.