Objective This study aimed to establish an analytical method based on ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） for six grayanane-type diterpenoid toxins. The method was applied to detect these toxins in honey samples involved in poisoning incidents. Clinical symptoms were analyzed alongside the field epidemiological results.Methods Honey samples were extracted and purified via the QuEChERS （Quick， Easy， Cheap， Effective， Rugged， and Safe） method， and subsequently analyzed by UPLC-MS/MS for qualitative and quantitative determination. In addition， abnormal clinical indicators were assessed based on field epidemiological findings and laboratory test reports.Results The validated method demonstrated good linearity （R2≥0.997） in the range of 1-400 ng/mL. The limit of detection （LOD） and limit of quantification （LOQ） were 0.13-0.30 ng/mL and 0.44-0.99 ng/mL， respectively. Spiked recoveries ranged from 90.6% to 107.6% with relative standard deviations （RSD） ≤6.6%. Rhodojaponin Ⅲ was detected in honey samples at concentrations in the range of 0.606-43.976 mg/kg. Patients presented symptoms consistent with Rhodojaponin Ⅲ poisoning， including dizziness， peripheral paresthesia， blurred vision， palpitations， and sinus bradycardia.Conclusion The established UPLC-MS/MS method is rapid， sensitive， and reliable for the determination of grayanane-type diterpenoid toxins. Furthermore， this honey poisoning incident was conclusively attributed to Rhodojaponin Ⅲ.