Abstract: The 10 g of honey sample was taken, 25 μL of 10 mg·L⁻¹ codeine-d₃ isotope internal standard solution was added, and then 10 mL of water and 10 mL of acetonitrile were added in sequence. The mixture was shaken evenly for 5 min, and 1 g of sodium chloride and 4 g of magnesium sulfate were added in sequence. The mixture was shaken evenly for 2 min, and centrifuged for 5 min. An aliquot (1 mL) of the supernatant was taken, and placed into a QuEChERS purification tube containing 37.5 mg of N-propylethylenediamine (PSA) and 150 mg of magnesium sulfate. After vortexing and mixing evenly, the mixed solution was centrifuged for 5 min. All the supernatant was taken, and diluted to 1 mL with acetonitrile. The solution obtained was passed through a 0.22 μm filter membrane, and the filtrate was determined by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). In chromatographic analysis, Acquity BEH C₁₈ chromatographic column was used as the stationary phase, and gradient elution was performed using a mixture of 2 mmol·L⁻¹ ammonium acetate solution containing 0.1% (volume fraction) formic acid and acetonitrile at different volume ratios as the mobile phase. In the mass spectrometry analysis, the positive ion mode of the electrospray ion source was used for ionization, Scheduled MRM mode was used for collecting signals, and the matrix matching method combined with the internal standard method was used for quantification. It was shown that linear relationships between the ratios of corresponding peak area to internal standard peak area and mass concentrations of 21 phytotoxins were found in the range of 0.1-200 μg·L⁻¹, with detection limits (3S/N) of 0.1 μg·kg⁻¹. Test for recovery was made according to the standard addition method, giving recoveries in the range of 75.1%-126%, and RSDs (n=6) of the determined values obtained from intra-day and inter-day precision tests were found in the ranges of 1.1%-14% and 1.4%-14%, respectively. The proposed method was used for the analysis of 30 honey samples, and rotenone, brucine, and strychnine were detected in 2 samples, with detection amounts of 0.36, 0.15, 0.18 μg · kg⁻¹, respectively.