Abstract: A pre-column derivatization method combined with UHPLC-MS/MS was developed for the simultaneous determination of salidroside and tyrosol in Beagle dog plasma. After protein precipitation by acetonitrile, the liquid supernatant was treated with dansyl chloride under dark conditions at 60℃ for 30 min, and then, the sample solution was extracted using methyl tertiary butyl ether. The multiple reaction monitoring in positive ion mode was used for MS detection of the tested analytes with the specific ion transitions of m/z 534.2→372.0 for salidroside derivative, m/z 372.0→171.0 for tyrosol derivative and m/z 506.0→171.0 for arbutin derivative. The chromatograph separation was achieved on an ACQUITY UPLC^® BEH C₁₈ column (100 mm×2.1 mm, 1.7 μm) with a gradient mobile phase consisting of acetonitrile (0.1% formic acid)-water (10% acetonitrile, 0.1% formic acid) for 9 min. The assay showed a good linearity over the range of 0.02/0.1-20/10 μmol·L^-1 with a lower limit of quantitation of 0.02 and 0.1 μmol·L^-1 for salidroside and tyrosol in dog plasma, respectively. The intra-and inter-day precisions were all less than 8.68%, and the accuracy was within ±11.4%. The established method with a high sensitivity, good specificity and reliability was appropriate for simultaneous determination of salidroside and tyrosol in dog plasma and successfully applied to a pharmacokinetic study after intragastric administration of salidroside to Beagle dogs.