A rapid and sensitive ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed for simultaneous determination of nine active constituents,uralsaponin C,uralsaponin F,22-acetoxyl-glycyrrhizin,24-hydroxy-licorice-saponin E2,licorice-saponin G2,licorice-saponin E2,22-acetoxyl-glycyrrhaldehyde,glycyrrhizin,and licorice-saponin J2,from licorice total saponins (LTS) in dog plasma.Ardisiacrispin A was used as the internal standard (IS).The separation was performed on Thermo Syncronic C18 column (100 mm×2.1 mm,1.7 μm) at a flow rate of 0.4 mL min?1,and acetonitrile-0.1% formic acid was used as mobile phase.The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization (ESI) source with negative ionization mode.All calibration curves have good linearity (r > 0.991) over the concentration range from 2.03 – 405 ng/mL to 2.63 – 2625 ng/mL for all components.The intra- and inter-day precision (RSD %) was within 15% and the accuracy ranged from 85.92 % to 113.8%.The method was successfully applied to pharmacokinetic study of nine triterpenoid saponins in dog plasma after oral administration of LTS.