Abstract: Eight isomers of 2 organic chlorine pesticides,BHC and DDT,present as residues in cereal crops,were determined by gas chromatography with capillary column.In the pretreatment of cereal samples,vortex oscillation and cooling at 4-6 ℃ of the sample mixture were adopted to prevent the formation of emulsion.Six kinds of grain samples,namely black soya bean,seed of Job′s tear,lotus seed,Gorgon fruit,soybean and broad bean,were analyzed by the proposed method for the residual amounts of the pesticides.Test for recovery was made by standard addition method,giving results in the range from 84.5%-103.2%.Values of relative standard deviation found were less than 5%.Detection limit of the method was found to be 5 μg·kg-1 for all the 8 isomers determined.