Abstract: An analytical method was developed for simultaneous determination of carbosulfan and other metabolites in Chinese cabbage.The analytes were extracted from the dispersed samples with diatomite by accelerated solvent extraction (ASE) using methylene chloride as solvent,purified with solid phase extraction column (SPE),analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electro-spray ionization (ESI+) with multi-reaction monitoring (MRM) mode,and quantified by matrix internal standard method.The recoveries ranged from 85% to 122% with relative standard deviations (RSD) varying between 2.3% and 12.5%.The limits of detection (LOD) were from 0.002 to 0.01 mg/kg and the limits of quantification (LOQ) from 0.005 to 0.02 mg/kg.The developed method was successfully applied to study dissipation of carbosulfan in Chinese cabbage,the short half-life of 0.9 d showed that carbosulfan can be quickly degraded to its three metabolites.The maximum residue of carbofuran was exhibited in the day of application,and dissipated about 70% in 1 d.However,the maximum residues of 3-hydroxycarbofuran and 3-keto-carbofuran were exhibited 1 d after application,and were quickly dissipated in Chinese cabbage.