Abstract: The sample of human urine (1.00 mL) was extracted by self-made extraction device. The extract was collected. UHPLC-MS/MS was applied to the rapid determination of 4 mercapturic acids in the extract. Waters Acquity UPLC^TM BEH C₁₈ chromatographic column was used as stationary phase, and the mixture of 0.05% (φ) acetic acid solution and methanol mixed in different ratios was used as mobile phase in gradient elution. ESI^- and multi-reactions monitor mode were adopted in MS/MS. Internal standard method was used for quantitative. Detection limits (3S/N) and lower limits of determination (10S/N) of the 4 mercapturic acids were in the ranges of 0.012-0.082 μg·L^-1 and 0.038-0.270 μg·L^-1 respectively. The proposed method was applied to the analysis of the sample of human urine. Values of recovery and RSDs (n=7) of intra-day were in the ranges of 93.9%-102% and 2.0%-3.4% respectively. Values of recovery and RSDs (n=7) of inter-day were in the ranges of 93.4%-102% and 2.4%-4.1% respectively.