Abstract: Antimicrobial peptide ( AMP) has been considered as a potential alternative to antibiotics and can kill bacteria used as natural preservative.In this study, effect of antimicrobial peptides from Bombyx mori ( CecropinXJ) on the changes of physical sign indexes in mice by gavage were observed, as well as organ damage was detected. The recombinant CecropinXJ produced by prokaryotic induced expression in large quantities was isolated and then poured into mouse stomach. The effect of CecropinXJ on the bodyweight, visceral coefficient ( liver, stomach, spleen, pancreas) in mice were analyzed and the pathological condition of visceral was observed.The results showed that CecropinXJ could not affect the body weight and visceral ( stomach, spleen, pancreas) coefficient of mice ( p > 0.05) , but affect liver coefficient ( p < 0.05) . It would provide scientific basis for safety applications of CecropinXJ products.