Abstract: Nine organochlorine pesticides were determined by gas chromatography with electron capture detector (ECD) after samples pre-treatment by liquid-liquid extraction with n-hexane and purified with concentrated sulfuric acid. The double capillary columns of Rtx-5MS and Rtx-1701 were used for identifying the target compounds. The experimental conditions were optimized and two surrogates were chosen for quality control. The detection limits of the method for 9 organochlorine pesticides were in the range of 0.0017~0.0079 μg/L with linear ranges of 0.5~100 μg/L. The recoveries were 74.7%~105.1% with the precision of 4.2%~9.3% RSD (n＝7). The method provides the advantages of low detection limits, good accuracy and precision, simple operation and is suitable for routine analysis of organochlorine pesticides in water samples.