OBJECTIVE To establish a quantitative analysis method for sennoside A, sennoside B and physcion by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS The sample was extracted by methanol-2 mmol/L ammonium formate(9∶1) at 40 ℃ for 1 h. The separation was performed using Agilent Eclipse Plus C_(18 )(2. 1 mm × 50 mm, 1. 8 μm) column with gradient elution. The mobile phase was consisted of 0. 1% formic acid and methanol. Qualitative and quantitative analysis was conducted with an electrospray ionization source operated in the negative ionization(ESI~-) mode and multiple reaction monitoring(MRM) mode. RESULTS The linear range of three compounds were from 0. 1 to 10 μg/mL with the correlation coefficients(r) above 0. 995. The spiked recoveries were in the range of 81. 9% to 114. 5% at the concentrations of 0. 02, 0. 15 and 1. 60 mg/g with relative standard devisions(RSDs) ranged from 0. 30% to 3. 43%(n=6). The detection limits of sennoside A and sennoside B were 1. 2 μg/g. The detection limit of physcion was 2. 4 μg/g. Sennoside A, sennoside B or physcion were detected in 19 out of 40 batches of samples. The content of sennoside A ranged from 0. 184 to 6. 33 mg/g and the content of sennoside B ranged from 0. 202 to 7. 23 mg/g. The content of physcion ranged from 0. 042 to 0. 79 mg/g. CONCLUSIONS The method is simple, accurate and suitable for the determination of sennoside A, sennoside B and physcion.