A liquid chromatography-tandem mass spectrometric（LC-MS/MS） method was established for the determination of glufosinate-ammonium residue in vegetables and fruits.The samples spiked with d3-glufosinate，the internal standard，were extracted with water，defatted with dichloromethane，and cleaned up using a strong cation exchange column，then derived with 9-fluorenylmethylchloroformate（FMOC-Cl） overnight.The separation of the target compound was performed on a C18 column（4.6 mm×50 mm，1.8 μm） using 5 mmol/L ammonium acetate（containing 0.1% formic acid）-acetonitrile（containing 0.1% formic acid） as mobile phase.The identification and quantitation of glufosinate were performed by MS/MS in positive electrospray ionization（ESI+） and multiple reaction monitoring（MRM） mode.The quantitative analysis was carried out by the internal standard method.The calibration curve showed a good linearity in the range of 0-200 μg/L with a correlation coefficient greater than 0.995.The limit of detection（LOD） and the limit of quantitation（LOQ） of this method were 10 μg/kg and 20 μg/kg，respectively.The average recoveries of glufosinate in foods at three spiked levels of 20，200,500 μg/kg were in the range of 80.8%-102.2% with relative standard deviations（RSDs） of 1.8%-7.9%.The application of internal standard effectively reduced the influence of matrix effects.The results of validation tests indicated that the method was sensitive and accurate,and was suitable for the monitoring of glufosinate residue in vegetables and fruits.