The present study was designed to develop a sensitive and selective specific high performance liquid chromatography (HPLC)-tandem mass spectrometric method (MS/MS) for the determination of ligupurpurosides B and C in rat plasma.The samples were prepared after protein precipitation and analyzed by liquid chromatography equipped with a C18 column interfaced with a triple quadrupole tandem mass spectrometer using ESI as the ionization source in the negative ion mode.The mobile phase consisted of water (0.01％ formic acid)-methanol (57:43,V/V) at the flow rate of 0.3 mL·min-1.The analytes and internal standard acteoside were both detected by use of multiple reaction monitoring mode.The total run time was 6.0 min.The method was linear in the concentration range of 2.5-500.0 ng·mL-1 and the lower limit of quantification (LLOQ) was 2.5 ng·mL-1.The intra-day and inter-day relative standard deviations across three validation runs over the entire concentration range were less than 9.8 ％.The accuracy determined at three concentrations was within ± 6.1％ in terms of relative error.In conclusion,this assay offers advantages in terms of expediency and suitability for the analysis of ligupurpuroside B and ligupurpuroside C in various biological fluids.