Abstract: ObjectiveTo explore anti-Escherichia coli(E.coli)mechanism of antibacterial peptides from Musca domestica larvae secretion.MethodsElectron microscope,sodium dodecyl sulfonate-polyacylate gel electrophoresis(SDSPAGE),and flow cytometry were used to study the anti-E.coli mechanism of antibacterial peptide extracted from housefly (Musca domestica)larvae.Results The bacterial number decreased obviously and the endoenzyme leaked out after the treatment of antibacterial peptide.Transmission electron microscope showed that the bacterial cells shrinked and became smaller and thinner.The cell contents of E.coli leaked out.SDS-PAGE electrophoregram showed that some of the solubility proteins of the bacterium diminished or even vanished and some new protein bands appeared.Cell cycle was affected and the count of bacteria increased in phase I but reduced in phase R(11.89% vs 45.25%)compared to that of the control.And the E.coli went into declining phase directly instead of normal logarithmic phase.ConclusionThe permeability of cellular membrane of bacteria and the synthesis of protein associated with growth and cleavage of bacteria were changed by the antibacterial peptide.