An analytical method was established for the simultaneous determination of 24 pesticides in putrefied blood by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF-MS)．The QuEChERS(Quick，Easy，Cheap，Effective，Rugged，and Safe) method was used for sample preparation．The analytes were extracted with acetonitrile-waters(4∶1) by supersonic， dehydrated by adding anhydrous magnesium sulfate，and penetrated with 0.22 μm membrane．The separation of 24 target compounds were performed on an ACQUITY UPLCTM HSS C18 column with gradient elution using acetonitrile-0.1% formic acid/ammonium formate as mobile phase.MS acquisition under positive ion mode was used to obtain accurate relative molecular masses and fragment ions．As a result，the limits of detection(LOD，S/N=3) of the target compounds were in the range of 0.43-10.0 ng/mL．The average recoveries of 24 analytes at three spiked concentration levels ranged from 61% to 98% with relative standard deviations of 1.5%-16.9%.This method could be applied in the analysis of 24 pesticides in putrefied blood due to its fastness，simplicity and relatively high sensitivity．