Abstract: Cbf-14 is a novel antimicrobial peptide composed of 14 amino acids.An optimized reversed phase high-performance liquid chromatographic method with electrospray-ionization quadrupole time-of-flight mass spectrometer (LC-ESI-QTOF/MS) method was developed for separation, identification and characterization of structurally related peptide impurities in Cbf-14 gel.Chromatographic separation was carried out on an Agilent ZORBAX SB-Phenyl column (150 mm × 4.6 mm, 3.5 μm), with acetonitrile-20 mmol/L ammonium formate buffer (adjusted to pH 3.0 with formic acid) as eluent using gradient elution.Under the established conditions, Cbf-14 and its structurally related peptide impurities were well separated; and a total of 24 impurities were detected and identified, of which 5 were impurities in the preparation manufacturing process and 19 were stressed products.Based on high resolution mass spectrometry analysis, the origins and formation mechanisms of these impurities were located.The obtained results are useful for the establishment of the manufacturing process, storage condition and quality control of Cbf-14 gel.