An analytical method was developed for the simultaneous determination of 24 insecticide residues in cucumber and tomato by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The samples were firstly extracted with acetonitrile,then purified by QuEChERS method and centrifuged at a high speed,finally filtered with a 0.22 μm membrane filter before UPLC-MS/MS determination.The results indicated that there were good linear relationships for 24 kinds of insecticides in the concentration range of 0.1-50 μg/L with the linear correlation coefficients(r2) more than 0.99.The average recoveries for the target compounds at four spiked levels of 0.002,0.01,0.1,1.0 mg/kg were in the range of 70.3%-110% with the relative standard deviations less than 15%.The limits of quantitation(LOQs) and the limits of detection(LODs) of the method were in the ranges of 0.05-5 μg/kg and 0.01-1.82 μg/kg,respectively,which could meet the detection requirements.This method is suitable for the simultaneous detection on 24 insecticides in cucumber and tomato with the advantages of high sensitivity,accuracy and efficiency.