A rapid method was developed for the determination of penicillin G and its two metabolites（penillic acid and penilloic acid） residues in citrus by dispersive solid phase extraction/ultra high performance liquid chromatography-tandem mass spectrometry（DSPE/UPLC-MS/MS）.The citrus samples were extracted with 80% acetonitrile,then purified with C18.The analytes were separated on an Acquity UPLCHSS T3 column with acetonitrile and 01% formic acid solution as mobile phases by gradient elution,and finally detected by tandem mass spectrometry in positive ESI mode（ESI+）.Identification and quantitation were performed by UPLC-MS/MS under multi reaction monitoring（MRM） mode and matrix matched standard curve method,respectively.Results showed that three analytes could realize an effective and rapid separation within 5 min.There were good linear relationships for the analytes in the concentration range of 5-2 000 μg/L with their correlation coefficients（r2） not less than 0.998 1.The limits of detection（LOD） and limits of quantitation（LOQ） of the method were in the ranges of 0.5-1 μg/kg and 5-10 μg/kg,respectively.The spiked recoveries for penicillin G and its metabolites in blank citrus samples were in the range of 76.7%-107%,with relative standard deviations（RSD） of 1.3%-9.6%.The method is rapid,simple,sensitive and accurate,and is suitable for the determination of penicillin G and its two metabolite residues in citrus.