[Objective]The research aimed to study antibacterial substance produced by induction of the larvae of the housefly with Bacillus subtilis.[Method]The antibacterial activity of the extract of the housefly larvae induced by Bacillus subtilis and the stability to the temperature,pH and ion strength were studied.[Result]The extract of the housefly larvae induced by Bacillus subtilis was inhibitory to six pathogens and engineered bacteria E.coli JM 109,being more potent to Gram positive bacteria.The antibacterial effect of the induced group was higher than the non-induced.The antibacterial substance of housefly induced by Bacillus subtilis had good temperature stability,and remained high antibacterial activity in the range of pH 4~10,and gradually lost its activity with the ion strength increasing.[Conclusion]The research provided theoretical basis for the application of antibacterial substance in the feedstuff.