Abstract: A method for detecting mebendazole and its metabolites in cattle and sheep products was established by EMR-Lipid-ultra-performance liquid chromatography-tandem mass spectrometry. The samples were first extracted by oscillation with 0.2% ammoniated acetonitrile solution, then freeze centrifugation, purified by Captiva EMR-Lipid column and directly analyzed by LC-MS/MS. The 3 kinds of mebendazole drugs were separated by SB-C₁₈ column (2.1 mm×100 mm, 1.8 μm) and gradiently eluted with acetonitrile and 0.1% formic acid water solution as mobile phase. The detection of mebendazole drugs was performed by tandem mass spectrometry in electrospray ionization under multiple reactions monitoring (MRM) mode. Matrix matching standard working curve and internal standard method were used for quantification. The calibration curves for target compounds were linear over the range of 0.2~50 ng/mL with correlation coefficients larger than 0.999. The detection limits (S/N>3) of 3 kinds of mebendazole drugs were 0.3 μg/kg. The recoveries of the 3 kinds of mebendazole drugs at three added levels were between 80.5% and 108.0%．The relative standard deviations were 1.1%~5.8%. The method overcame the current shortcomings of cumbersome preprocessing and long detection cycle, and it was simple in operation and accurate in results. The method was applicable to the rapid detection of mebendazole and its metabolites residues in cattle and sheep products.