The invention discloses a method for preparing antioxidant peptide by utilizing pancreatin to hydrolyze rice residue. The antioxidant peptide is obtained by adopting rice residue, namely a byproduct of aginomoto production as a raw material, concentrating the rice residue to extract rice residue protein by virtue of an pickling method, hydrolyzing the rice residue protein by adopting pancreatin, centrifuging, hyperfiltering and freeze drying the rice residue, the enzymolysis condition is as follows: after the rice residue protein is mixed with water at a mass-to-volume ratio of (1:6)-(1:9), the pH value is adjusted to 7.5 to 8.0 by adding hydrochloric acid, and the pancreatin which accounts for 6-8wt% of the rice residue protein is added at the temperature of 45-55 DEG C to enzymolyze the rice residue protein for 5-6 hours. The production cost is low, the process is simple, environmental friendliness is realized, the obtained antioxidant peptide has the characteristics of reasonability in ammonia acid constitution, low irritability, safety, reliability and the like, the content of total phenols is 34.47mg / g, the IC50 value of DPPH free radical and hydroxyl free radical is respectively 2.27mg / mL and 2.98mg / mL, and the elimination capacity is good, so that the antioxidant peptide is strong in antioxidant activity and a functional food base material with potential.