Abstract: The sample of chicken was extracted with acetonitrile,and the extract obtained was purified by ultrafiltration membrane to intercept those substances with relative molecular mass≥1 000 Da.The contents of the 4 organochlorine pesticides including aldrin,dieldrin,dicofol and chlorobenzilate,in the sample solution,were determined by GC-MS.Under the optimized conditions of ultrafiltration,values of lower limit of determination (10S/N) of 4 organochlorine pesticides obtained were 0.05 mg·kg-1.