Abstract:This study conducted uncertainty evaluation on eight pesticide residues in vegetables by adopting the liquid chromatography-tandem mass spectrometry method.According to the National Food Safety Standard—Determination of 331 Pesticides and Metabolites Residues in Foods of Plant Origin—Liquid Chromatography-tandem Mass Spectrometry Method （GB 23200.121—2021），a mathematical model was built to analyze the sources of uncertainty，with the uncertainty evaluated.At the spiking level of 0.020 mg/kg，the measurement results and uncertainties of acetamiprid，clothianidin，thiamethoxam，carbofuran，3-hydroxycarbofuran，carbendazim，isazofos，and pyraclostrobin were （0.018 4±0.004 6），（0.016 2±0.003 7），（0.017 9±0.004 6），（0.020 4±0.006 4），（0.018 6±0.004 4），（0.018 0±0.005 0），（0.016 0±0.003 6），and （0.018 2±0.004 4） mg/kg （P=95%，k=2）.The main sources of uncertainty are the preparation and dilution process of standard solutions and standard curve fitting，which should be strictly controlled during experiments.