Abstract: A purification and characterization of a novel antimicrobial peptide from from Bacillus licheniformis LY12 was explored. The novel antimicrobial peptide designated LYF12, was purified, with a procedure involving ultrafiltration, ion exchange chromatography (DEAE-Sepharose FF), gel filtration (Sephadex G-15), and everse phase HPLCs on C8 column and C18 column. LC-ESI-MS indicated the molecular mass of the purified peptide was 2750.785Da, which is in good agreement with the result of Tricine SDS-PAGE. .In vitro bioassays showed that LYF12 inhibits the growth of a variety of microbes, including filamentous fungi and bacteria. The minimum inhibitory concentrations (MIC) against Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Micrococcus aureus, Bacillus cereus, Vibrio parachaemolyticus were 9.8, 19.8, 20.7, 7.2, 9.6, 10.2 and 15.7μg/ml, respectively. The purified antimicrobial peptide exhibited antibacterial activity against Gram-positive and Gram-negative bacteria as well as fungi. Considering its promising properties, the antimicrobial peptidefrom Bacillus licheniformis LY12 may ?nd potential application in food industry.