Abstract: To investigate the regulatory function of fermented dietary fiber on intestinal flora, in this paper, wheat bran dietary fibers were fermented by white-rot fungi and then added into pasta samples in a certain proportion for in vitro gastrointestinal digestion and in vitro fermentation, the pH of the samples and short-chain fatty acids content in the metabolites were determined, and the 16S rRNA genes of each samples were sequenced by Miseq. The results showed that fermentation resulted in a significant increase in protein and SDF content in bran dietary fiber compared with unfermented dietary fiber; both fermented and unfermented bran dietary fiber significantly decreased intestinal pH and promoted the production of short-chain fatty acids, and at the same additive amount, the acid-producing capacity of fermented samples was significantly higher than that of bran dietary fiber; and both fermented and unfermented bran dietary fiber decreased the diversity of the intestinal flora, and increased the diversity of Lactobacillaceae HT002, Lactobacillaceae and other beneficial bacteria, and reduce the abundance of harmful bacteria such as Streptococcus and Escherichia-Shigella, and the former had a better microbial regulation effect than the latter, increased the abundance of Bacteroidetes and reduced the abundance of Firmicutes, and at the same additive amount, the F/B value of fermented wheat bran dietary fiber was always lower than that of wheat bran dietary fiber, which indicated that fermentation could improve its ability to regulate the intestinal flora. Fermentation could improve the regulatory effect of wheat bran dietary fiber on intestinal microorganisms and short-chain fatty acids, which resulted in higher prebiotic activity.