【Abstract】 Objective To establish an ultra-performance liquid chromatography- triple quadrupole tandem mass spectrometry (UPLC-MS/MS) method for the determination of 21 aconitine alkaloids in herbal liqueur. Methods The samples were diluted with a solution of 5 mmol/L ammonium acetate - 0.1% formic acid in water:methanol (90:10), filtered through a 0.22 μm PTFE membrane, and then separated using a Waters ACQUITY UPLC HSS T3 chromatographic column (100 mm × 2.1 mm, 1.8 μm). Gradient elution was performed with a mobile phase consisting of 5 mmol/L ammonium acetate - 0.1% formic acid in water and methanol. A sample volume of 1.0 μL was injected, and data was acquired in multiple reaction monitoring (MRM) mode. Quantification was performed using an external standard method. Results The linear ranges of the 21 aconitum alkaloids were wide, with good linear relationships and correlation coefficients (r) all greater than 0.999. The limits of quantitation (LOQs) ranged from 0.05 μg/L to 2.5 μg/L. At spiking levels of 10 μg/L, 20 μg/L, and 50 μg/L, the average recoveries of the 21 aconitum alkaloids in blank herbal liqueur matrices ranged from 94.38% to 110.58%, with relative standard deviations (RSDs) below 7.40%. The inter-day and intra-day precisions for all 21 target compounds were below 8.43%. Conclusion This method is simple, accurate, reliable, and reproducible, making it suitable for the determination of 21 aconitine alkaloids in herbal liqueur.