An on-line gel permeation chromatography combined with gas chromatography-mass spectrometric(GPC/GC-MS) method was developed for the determination of eighteen organochlorine pesticides in atmospheric dust.The sample was simplified by QuEChERS method,extracted with acetonitrile and cleaned with graphitized carbon black(GCB)，then filtrated by one step of centrifugation before detection.By this method,8-10 samples can be treated within 30 min，and after coupled with GPC purification，the analysis time could be shortened，and the working efficiency and the accuracy of results could be improved.The result indicated that the calibration curves were liner in the range of 0.025-2.0 mg/L， with correlation coefficients of 0.991 9-0.999 6.The limits of detection for the sample were in the range of 3.2-14.6 μg/kg and the limits of quantitation were 10.7-48.7 μg/kg.The mean recoveries of eighteen organochlorine pesticides at spiked levels of 0.2，1.0 mg/kg were in the range of 78.6%-117.3%，with relative standard deviations(RSDs，n=5) of 1.3%-5.1%.