A low temperature plasma ionization mass spectrometry with a thermal desorption device was developed for the direct and rapid screening of 8 organophosphorus pesticides in vegetables.The vegetable sample was extracted with acetonitrile,and the supernatant was analyzed by mass spectrometry after centrifugation.In the positive ion detection mode,the sample was placed on a heating block for desorption,ionized with a low temperature plasma,and then subjected to mass spectrometry.Results showed that there were good linear relationships for the 8 analytes in range of 0.005-0.200 mg/L with their correlation coefficients greater than 0.99.The detection limits were in the range of 0.001-0.010 mg/L.The recoveries for Chinese cabbage ranged from 90.5% to 119% with relative standard deviations(RSDs,n=6) of 12%-17%.The detection sensitivity was improved by 9.3 to 41.7 times compared with that without thermal desorption.With simple operation,easy pretreatment,high sensitivity and good accuracy,the method could be applied in the simultaneous determination of pesticide residues in vegetables,and has a great application prospect in non targeted analysis for large batch of samples.