A rapid method was developed for the determination of ethylenethiourea（ETU）residues in fruits by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）under multiple reaction monitoring mode.The samples were extracted with alkaline acetonitrile containing 1.5% NH3?H2O,cleaned-up by adding Florisil,separated on an HSS T3 column using acetonitrile-0.2% formic acid as mobile phase by gradient elution at a flow rate of 0.4 mL/min,and confirmed by positive electrospray ionization tandem mass spectrometry under multiple reaction monitoring（MRM）mode.The detection was quantified by the external standard method.The results indicated that the calibration curves of ETU were linear in the range of 5-200 μg/L with correlation coefficients more than 0.999.The average recoveries of ETU in five fruit samples at three spiked levels of 5,20,50 μg/L were in the ranges of 93.6%-101.4%（apple）,91.2%-98.4%（peach）,84.6%-95.1%（grape）,86.8%-97.9%（citrus）,and 79.5%-96.3%（banana）,respectively.The limits of detection（LOD）for these five fruits were 0.08,0.13,0.11,0.23,0.26 μg/L,and the limits of quantitation（LOQ）were 0.28,0.42,0.37,0.75,0.86 μg/L,respectively.The method is simple,accurate,economic and friendly to the environment,and could meet the requirements for rapid determination of ETU residues in fruits.