In order to improve the bioaccessibility of polyphenols and antioxidant activity in naked oats， this study was conducted with in vitro simulated digestion model and colonic fermentation model to compare the changes of total phenol content and antioxidant activity of germinated and un-germinated naked oat at different digestion stages and colonic fermentation stage， and to further explore the bioaccessibility of sprouted naked oat. In the simulated digestion stage in vitro， the bioaccessibility of polyphenols， DPPH free radical scavenging and hydroxyl free radical scavenging in germinated naked oats were the highest in intestinal digestion， which were 8.99%， 47.75% and 9.57% higher than those of un-germinated naked oats， respectively. The bioaccessibility of reducing power was the highest during gastric digestion， which was 39.82% higher than un-germinated naked oat. At the colonic fermentation stage， the highest polyphenol content and antioxidant activity in digestive residue of naked oats were found at 24-30 h. The bioaccessibility of polyphenols， DPPH scavenging ability and hydroxyl free radical scavenging ability of un-germinated naked oat digestion residue were 8.83% higher than that of germinated naked oat digestion residue， 8.16% higher than that of germinated naked oat digestion residue， and 16.68% higher than that of germinated naked oat digestion residue. However， it is almost equal to the bioaccessibility of the gastrointestinal digestive stage. These results indicate that germination can not only significantly improve the bioaccessibility of naked oats polyphenols and antioxidant activities in the gastrointestinal tract， but also maintain relatively high bioaccessibility of polyphenols in colonic fermentation， which provided a new idea for improving the bioavailability of cereal polyphenols in human digestive tract.