In order to extract antimicrobial peptides from Bacillus subtilis and explore its anti-corrosion effect on food, three strains of B. subtilis DZSY21, Bacillus amylolysis FZB42 and B. subtilis OKB105 were selected for fermentation in this experiment, and then the fermentation supernatants of the three strains were mixed with acetone at a volume ratio of 1:2. The crude extracts of antimicrobial peptides from three strains were obtained by rotary evaporation concentration. According to the thermal stability test of the antimicrobial peptides, the antibacterial effects of the antibacterial peptides from the three bacteria were all slightly reduced after heating at 100 ℃ for 30 min, but the anti- bacterial activities still kept strong. The antimicrobial peptides of the three strains were sensitive to trypsin and papain. Milk, apple, meat and other food models were used in the application experiment, and the results showed that the experimental group was significantly better than the control group after treated with B. subtilis DZSY21 antimicrobial peptide, indicating that B. subtilis DZSY21 antimicrobial peptide has better antiseptic effect.