Lotus seed is the traditional health food with medicinal value in China. Many peptides with easy absorption and biological activity were prepared from protein by enzymatic hydrolysis. In this study, the extraction parameters of protein from lotus seed were optimized by using salt extraction method. The results indicated that lotus seed protein extraction rate reached 42.48% when NaCl concentration was 0.1mol/L and the ratio of solid and liquid was 1:40. Then, lotus seed protein was hydrolyzed by trypsin, and biological activities of peptides were assayed by using pyrogallol self-oxidation method. The results showed that the bioactive peptide preparation is oxidant when the ratio of enzyme and substrate is 5%. However, the bioactive peptide preparation is antioxidant when the ratio of enzyme and substrate gradually increase to 7.5%, 10%, 15% and 25%.