Objective: The residues of BHC（α-BHC

β-BHC

γ-BHC

δ-BHC）

DDT（op′-DDD

pp′-DDD

op′-DDT

pp′-DDT） and PCNB in Radix Rehmanniae were determined by GC /ECD.Method: The samples were extracted by the SFDA method.The capillary column was SPB-608（30 mm × 0.25 mm

0.25 μm）;carrier gas N2（99.999%

1 mL·min-1）;The injector temperature was 230 ℃;The column temperature program: the initial temperature was 100 ℃

up to 220 ℃ with the rate of 10 ℃·min-1 rate of 8 ℃·min-1 to 250 ℃（hold 10 min）.Result: The average recovery was 89.8%-101.3%.The lowest detection concentration was 1.0-10.0 ng·g-1.The relative standard deviation was 4.7%-8.4%.The method was rapid and accurate.