Abstract: Abstract: Objective The purpose of the study was to analyze the cecropin antibacterial activity and different component of antibacterial peptide in different growth stages. Material and Methods Tenebrio Molitor produced antimicrobial peptides in different stages, after infected E. coli with the method of acupuncture. Antimicrobial peptides were obtained after grinding and centrifugating the infected Tenebrio Molitor, and determined antimicrobial effects of these antimicrobial peptides with drug-test. Protein and polypeptide were separated with the method of polyacrylamide. Results The results of the sensitivity test showed that bacteriostasis effect of antibacterial peptide of Tenebrio Molitor in the larval stage was more effect than that of antibacterial peptide of Tenebrio Molitor in the pupa and the adult phase, but there was no significant difference. Tenebrio Molitor electrophorogram showed that there were 8 genophore in larvae stage, 5 genophore in prosopon, and 5 genophore in pupa. The result showed that the variety of antimicrobial peptides of Tenebrio Molitor in pupa and adult was less than that of in larvae, however, more little peptide were not separated from. Tenebrio Molito of each stage.