Abstract: OBJECTIVE To establish a determination method for metronidazole, dimetridazole, ronidazole, ipronidazole and their metabolites 1-(2-hydroxyethyl)-2-hydroxy-methyl-5-nitroimidazol, 2-hydroxymethyl-1-methyl-5-nitroimidazole and hydroxy-ipronidazole in acne dispelling cosmetics. METHODS The sample was extracted with 0.1% formic acid-acetonitrile, and then purified by QuECHERS method. The separation and analysis was performed on a ZORBAX SB-C₁₈ column. The mobile phase consisted of 0.1% formic acid acetonitrile -0.1% formic acid aqueous solution by gradient elution, electrospray ionization(ESI) source was applied and operated in the positive mode. Multiple reaction monitoring(MRM) mode was used to monitor ions. External standard method was used to quantitative calculation. RESULTS Seven target analytes showed good linear relationship in the range of 5.0-500.0 ng·mL^-1. The linear correlation coefficients of the method were > 0.995. At three levels, the average recoveries ranged from 87.9% to 114.9%, with the RSD(n=6) from 0.4% to 4.5%. The limits of quantification of the method were among 5-40 μg·kg^-1, and the limits of detection were among 1.4-12.0 μg·kg^-1. CONCLUSION This method has good purification effect, it is simple and rapid, which can be applied to the detection of nitroimidazoles antibiotics and their metabolites in acne dispelling cosmetics.