Abstract: A method for the determination of residual cypermethrin in pyrethrins WE by GC-MS was proposed.The sample of pyrethrins WE was extracted with ethyl acetate by high-speed homogenizer,and the extract obtained was purified on SPE column.The eluate was determined separately by the dual column (including a weak polarity column and a medium polarity column) gas chromatography and the hyphenated GC-MS.It was found that in using only the dual column-GC for analysis of complex samples,the results obtained might be false positive.Linearity range of cypermethrin was kept from 0.1 to 4.0 mg·L-1 by GC-MS,with detection limit of 0.04 mg·L-1.Values of recovery of the method found were in the range of 82.5%-90.0%.