An extraction method for bound polyphenols (BPs) in red rice bran dietary fiber (RBDF) was developed and optimized, followed by analysis of the chemical composition and functional activities of RBDF-BPs. Conditions for BP extraction were optimized through single-factor experiments combined with the Box-Behnken response surface methodology. Alkaline hydrolysis was found to be more effective than acid hydrolysis in releasing RBDF-BPs, with a maximum total phenolic content (TPC) of 144.79 mg GAE/g DM obtained using the former method. A total of 21 polyphenolic compounds were identified by systematic quantitative analysis of RBDF-BPs using UPLC-ESI-QTOF-MS/MS, and 15 main components were subjected to targeted quantification using UPLC-ESI-QQQ-MS/MS. The in vitro antioxidant activities of RBDF-BPs were comprehensively assessed via DPPH•, ABTS+•, and •OH radical scavenging assays. RBDF-BPs exhibited significantly stronger in vitro antioxidant activities than vitamin C. RBDF-BPs also exerted dose-dependent inhibitory effects on both α-amylase and α-glucosidase, with the inhibitory effect on α-glucosidase being notably stronger (IC50=14.54 μg/mL). In the present study, the optimal extraction process of RBDF-BPs was determined, the composition and content of the chemical components of RBDF-BPs were elucidated, and their antioxidant activities and hypoglycemic potential were verified. The results of this study may serve as a scientific basis for the application of RBDF-BPs in functional foods and chronic disease prevention.