The invention relates to a method for increasing output of bacillus subtilis antibacterial peptide through knock-out of phrC genes, and belongs to the technical field of biology. According to the method, a high-yield antibacterial peptide bacterial strain FMB25 is established by constructing a gene knockout vector with bacillus subtilis ATCC9943 as an original strain and escherichia coli cloning vector pGEM-T as skeleton and knocking out the phrC gene of bacillus subtilis ATCC9943 genome through double exchange based on the principle of homologous recombination. According to analysis of high performance liquid chromatography, improved bacterial strains have substantially enhanced capability of yielding surfactin and fengycin.