The aim of this study was to prepare a new antioxidant peptide-containing dairy beverage by the fermentation of Lactobacillus paracasei. The fermentation conditions and medium ingredients were optimized based on final viable cell count, acidity, peptide concentration, peptide yield, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. A shaking speed of 180 r/min, a fermentation time of 24 h, an inoculum size of 5％, a skim milk powder concentration of 12％ and a glucose concentration of 6％ were found to be the optimal conditions to obtain the highest peptide concentration of 0.98 mg/mL, highest final viable cell number of 8.5 × 108 CFU/mL and highest DPPH radical scavenging activity of 62.38％.