Abstract: Objective: To study the effect of the fly maggot peptide on the of aging mice and the related mechanism.Methods: 60 mice were randomly divided into six groups.Except the blank group,the other five groups including aging model group,vitamin C group and fly maggot peptides of low,middle and high dose group( 2,4,8 g / kg / d) were induced aging with D- galactose.The spleen and thymus index of mice were measured. The hydroxylamine method was used to determine the superoxide dismutase( SOD) activity in mice's liver,brain and serum. The activity of catalase( CAT) and glutathione peroxidase( GSH- Px) was determined by the visible light method,the content of malondialdehyde( MDA) was determined using thiobarbituric acid( TBA)method.Results: Compared with the blank group,the spleen index,thymus index and liver index of model group were reduced significantly,and the fly maggot peptides of low,middle and high dose group organ index were significantly increased( p < 0.05).Compared with the blank group,the SOD,CAT,GSH- Px in liver,brain of model group were decreased,and MDA was increased( p < 0.05),CAT,SOD in serum were decreased,MDA content was increased( p < 0.05).Compared with the model group,SOD,CAT,GSH- Px in liver and brain tissue of low fly maggot peptides,and the high dose group were significantly increased,MDA content was decreased significantly( p < 0.05).SOD,CAT content in serum were significantly increased,MDA in serum was reduced( p < 0.05). Conclusions: Fly maggot peptides can affect immune function of aging mice by changing the organ index of aging mice,change the antioxidant capacity by increasing the activity of SOD,CAT,GSH- Px in liver and brain tissue and reducing the content of MDA.The influence mechanism of fly maggot peptides on aging mice may be associated with the increasing of the activity of antioxidative enzyme and organ index change.