Objective To establish a rapid detection method for 81 illegal weight loss additives in tablet candy using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).Methods Samples were ultrasonically extracted with 80% methanol-water (containing 0.1% formic acid), separated on a Waters ACQUITY UPLC HSS T3 column, and eluted with a gradient of methanol and 0.1% formic acid water solution. Detection was performed using multiple reaction monitoring (MRM) with simultaneous scanning in positive and negative electrospray ionization modes, and quantification was carried out using the external standard method.Results The 81 target analytes showed good linear relationships within their respective mass concentration ranges, with correlation coefficients greater than 0.990 0. The limits of quantification ranged from 0.01 to 0.40 mg/kg. The average recoveries ranged from 71.0% to 119.5%. The relative standard deviations for method precision and repeatability were all less than 13.5% (n=6).Conclusion The method is simple, rapid, highly accurate, and shows good repeatability, and is suitable for the detection of illegal weight loss additives in tablet candy.