By using the hydrolysis degree as the evaluation, the sheep lung enzymatic process was optimized to investigate the antioxidate activities of the enzymolysis products, hydrolyzed by neutral protease. On the basis of single factor studies, the response surface analysis (RSM) assay was then used to obtain the best enzymatic proscess. Our results showed that the optimal condition was as follows. The enzyme amount was 1 700.0 U/g, with solid-liquid ratio 2∶1(mL/g) , enzymatically hydrolyzed for 4 h at 50 ℃. Under this optimal conditions, 3 times of the replication experiments turned out that the error of the actual degree of hydrolysis (18.89%) was small, compared with the theory one (18.19%). Moreover, the absorption value of reducing power was found to be 0.472, and IC₅₀ of the DPPH radical scavenging rate, the superoxide anion radical scavenging rate, and the hydroxyl radical scavenging rate were 67 mg/mL, 40.07 mg/mL, and 31.88 mg/mL, respectively. These results of above detection indicated that enzymatic hydrolysates of sheep lungs possessed certain antioxidant activity in virto.