A method for the simultaneous determination of paeoniflorin, tetrahydropalmatine, jatrorrhizine, berberine, palmatine, evodiamine, saikosaponin C, saikosaponin A and saikosaponin D in Jiaweizuojin Pills was established by ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS). The UPLC separation was performed on a Zorbax RRHD Eclipse Plus C18 column (50 mm x 2.1 mm, 1.8 microm) by using 0.2% (v/v) formic acid aqueous solution and methanol as mobile phases with the gradient elution at a flow rate of 0.4 mL/min. The analytes were detected by tandem mass spectrometry under the positive ion mode with the electrospray ionization (ESI) source and in the multiple reaction monitoring (MRM) mode. Under the optimized conditions, the calibration curves were linear in the ranges of 0.025 -5.0 mg/L for paeoniflorin, 0.0010-2.0 mg/L for tetrahydropalmatine, 0.0023-7.2 mg/L for jatrorrhizine, 0.0027-28.9 mg/L for berberine, 0. 002 3 - 9. 1 mg/L for palmatine, 0. 005 0 -1.0 mg/L for evodiamine, 0.050-10 mg/L for saikosaponin C, 0.0050-1.0 mg/L for saikosaponin A and 0.0075-1.5 mg/L for saikosaponin D with the detection limits of 5.0, 0.20, 0.45, 0.54, 0.45, 1.0, 10, 1.0, 1.5 microg/L, respectively. The average recoveries of the nine effective components were between 99.3% and 105% with the relative standard deviations not more than 2.6%. The developed method is simple, rapid and accurate, and suitable for the quality control of the nine effective components in jiaweizuojin pills.