Abstract: high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method for the determination of diniconazole residues in the fruits has been developed. Samples are liquid-liquid extracted with acetone - hexane and clean up with dispersive solid phase extraction (DSPE). The analyte is separated on an ODS-C18 column with acetonitrile-0.1% formic acid solution as the mobile phase.The target compound is detected by LC-MS/MS (ESI +) under the multiple reaction monitoring (MRM) mode using an external standard method. The linear relationship of this method was good between 0.002~0.2 mg/L concentration range. The limit of quantification (LOQ) was 0.001 mg/kg. The recoveries of diniconazole ranged from 78.8% to 108.0% at the three spiked levels of 0.005~0.1 mg/kg and the relative standard deviations(RSDs) were in range of 2.1%~6.9%.