Abstract: UHPLC-MS/MS was applied to the simultaneous determination of 5 aconitum alkaloids, i.e. aconitine, hypaconitine, mesaconitine, yunaconitine and bullatine A in bloods. The blood sample (1 mL) was oscillated in 0.1 mol·L^-1 hydrochloric acid solution (4 mL) for 10 min, and then was centrifuged at the speed of 8 000 r·min^-1 for 30 min. The supernatant was purified with Waters Oasis MCX solid phase extraction column. ACQUITY UPLC^® BEH C₁₈ chromatographic column was used as stationary phase, and the mixture of acetonitrile and water (pH was adjusted to 10 with ammonia) mixed in different ratios was used as mobile phase in gradient elution. ESI⁺ and multi-reactions monitor mode were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 5 aconitum alkaloids were kept in the same range of 1.0-200 μg·L^-1, with detection limits (3S/N) in the range of 0.1-0.5 μg·L^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 75.6%-115%, with RSDs (n=6) in the range of 1.3%-6.5%.