Abstract: A method for determination of pyrethroid pesticides in aquatic products by GC-MS was proposed. The sample was extracted with a mixed solvent of cyclohexane and ethyl acetate (1+1), and the extract obtained was purified by gel permeation chromatography (GPC) to eliminate the interference of matrix. Eluate from the GPC column was taken up with 1.0 mL of mixture of cyclohexane-ethyl acetate (1+1), which was used for GC-MS determination. Using sample of carp as matrix, recovery and precision were tested by the standard addition method, giving values of recovery in the range of 75.2%-120% and values of RSD′s (n=6) in the range of 1.11%-13.7% respectively.