Excessive oxygen free radicals-induced apoptosis and tissue damage are acknowledged as key triggers of chronic diseases. Casein-derived active peptides offer novel approaches for the prevention and treatment of such conditions because of their antioxidant potential,. In this study, two high-yield protease-producing strains of Bifidobacterium lactis and Lactobacillus paracasei were selected and the casein plate method, furfurylphenol method, and paraformaldehyde method is used for fermentation. After that, the products were analyzed for antioxidant activity and the active peptide segments were identified. The results demonstrated that the casein peptides produced by this probiotic combination exhibited the strongest DPPH, ABTS, reducing power, and hydroxyl radical scavenging activity at a concentration of 10 mg/mL. Besides, the active components with molecular weights below 10 kDa (mainly distributed in the range of 1.0~2.5 kDa) were obtained via ultrafiltration, showing DPPH, ABTS, and hydroxyl radical scavenging rates of 65.6%, 83.8%, and 78.6% respectively. Further identification by LC-MS/MS revealed five novel antioxidant peptide sequences: DAQSAPLRVYVE, AQPTTMARHPHPHL, FLLYQEPVLGPVRGPFPIIV, AQSAPLRVYVEELKPTPEG, and DMPIQAFLLYQEPVLGPVR. In conclusion, this study provides theoretical and experimental foundations for the preparation of casein-derived antioxidant peptides and the development of functional foods.