A rapid and sensitive analytical method for the determination of thifluzamide residues in rice,corn and potato samples was established based on QuEChERS（Quick,Easy,Cheap,Effective,Rugged and Safe） and ultra performance liquid chromatography coupled with tandem mass spectrometry（UPLC-MS/MS）.The sample was extracted with acetonitrile,and then purified with primary secondary amine（PSA）.The mass spectrometer was operated with electrospray in the negative ion mode（ESI-）.The thifluzamide residues were quantified by the external standard method using the matched standard solution to compensate for matrix effect.Under the optimal conditions,the calibration curve showed a good linearity in the range of 1.0-1 000 μg?L-1 with a correlation coefficient of 0.999 0.The average recoveries of thifluzamide in rice,corn and potato at three spiked levels of 0.01,0.1,1.0 mg?kg-1 ranged from 89.1% to 109.3% with relative standard deviations（RSDs,n=5） of 3.5%-8.7%.The limits of detection（LODs） of thifluzamide were in the range of 0.009-0.015 μg?kg-1，and the limits of quantitation（LOQs） were 0.032-0.049 μg?kg-1．The method is simple,rapid and accurate,and could be adapted for the confirmation of thifluzamide residues in rice,corn and potato samples.