A method was developed for the simultaneous determination of 169 pesticides in grains by gas chromatography with tandem mass spectrometry (GC-MS/MS). The homogenized sample was extracted with acetonitrile, and then purified by QuEChERS, The targeted compounds were detected by GC-MS/MS system under the mode of multiple reaction monitoring (MRM). The results indicated that the limits of detection (LODs) of 169 pesticides were ranged from 0.3 to 13.0 μg/kg. The LOQs of the tested pesticides were between 1.0 and 40.0 μg/kg. In the linear range between 0.005 and 2.0 mg/L of each pesticide, the linear correlation coefficients were greater than 0.99. The average recoveries ranged from 65.3% to 143.6% and the RSDs of 97% pesticides were less than 20%. This method was suitable for the identification and quantification of multi-component pesticides in grains due to its simplicity, good purification and high sensitivity.