Abstract: Objective: the in vitro antioxidant capacity of silk reeling silkworm pupa protein hydrolysate was discussed and then a reference for the depth development and utilization of silk reeling pupa protein was provided.Methods:the reducing power and their scavenging activity against DPPH, superoxide anion, hydroxyl free radicals were investigated.Results: the hydrolysis product of special silkworm chrysalis protein hydrolysis enzyme had the maximum reducing power and after diluted the enzyme solution 100 times, the absorbance was 0.75.To O-2·and DPPH·, the scavenging activity were the highest, diluted the enzyme solution 10 times and 100 times respectively, the scavenging rate were 34.54% and 79.38%, respectively.The scavenging rate of ·OH was second, when the enzyme solution was diluted 10 times, the scavenging rate was 43.77%. Conclusion: the hydrolysate of special silkworm chrysalis protein hydrolysis enzyme showed a good antioxidant activity in vitro.