Abstract: GC-MS/MS was applied to the determination of 27 pesticide residues in edible oil. The sample was extracted with a mixture of cyclohexane and ethyl acetate (1+1) by vortex oscillation for 1 min. The extract was purified by gel permeation chromatography (GPC), concentrated to be nearly dry in the water bath of 50 ℃ and diluted to 1.0 mL with n-hexane. The analytes were separated on a HP-5MS column. EI and SRM were adopted in MS analysis. Linear relationships were founed between peak areas and mass concentrations of the 27 pesticides in the range of 10-500 μg·L-1, with detection limits (3S/N) in the range of 1.3-8.0 μg·kg-1. Tests for recovery were made at 3 concentration levels of 10, 100, 400 μg·kg-1, giving recovery rates in the range of 70.2%-108% and RSDs (n=6) less than 16%.