Abstract: In order to simultaneously determine residues of chlorpyrifos and cypermethrin in Brassica chinensis L. more accurately and more conveniently, a gas chromatographic method with micro-electron capture detector (GC-μECD) was developed. The pesticide residues were extracted from greengrocery with aceonitrile under ultrasonic wave and the extract was cleaned-up by self-made florisil solid-phase extraction column and eluted with acetone/n-hexane（1:9, V/V）. The eluent from column was evaporated to near dryness in water-bath with constant temperature and diluted with n-hexane to volume. The analytes were separated by a heated HP-5 capillary column, determined by GC with μECD and quantified by external standard of the peak area. The liner range of chlorpyrifos and cypermethrin were 0.005~5mg/L and 0.01~5 mg/L, with correlation coefficients（r）higher than 0.99. Mean recoveries of two analytes in Brassica chinensis L. ranged from 84.2% to 116.9% at spiked levels of 0.1~1mg/kg, and the relative standard deviations（n=3）from 2.4% to 12.7%. Limits of detection for chlorpyrifos and cypermethrin were 0.0002mg/kg and 0.003mg/kg, respectively. The method is simple, rapid, sensitive and can meet the requirements of pesticide residue analysis on accuracy and precision, thus practical for the simultaneous analysis of chlorpyrifos and cypermethrin residues in Brassica chinensis L..