Abstract: An ultra performance liquid chromatography-tandem mass spectrometric(UPLC-MS/MS) method was developed for the determination of the 110 pesticides in six Chinese herbal medicines.Pesticides were extracted with acetonitrile,cleaned up by PSA solid phase extraction column and then separated with UPLC and detected with MS/MS in multiple reaction monitoring(MRM) mode via positive electrospray ionization(ESI+).The method was validated at three fortification levels(LOQ,5 LOQ and 20 LOQ) in Panax ginseng C.A.Mey.,Astragali radix,Perilla leaf,Chrysanthemum,Motherwort herb and Chinese magnolivine fruit.The average recoveries of the 110 pesticides at three fortification levels were between 70.1%-95.7%,with relative standard deviations(RSDs) between 0.8%-13.7%.The standard calibration curves for 110 pesticides all showed good linearity over the range of 1/2 limit of quantification(LOQ) and 50 LOQ.The LOD of all the 110 pesticides in ginseng were between 0.1 μg/kg and 8.0 μg/kg,LOQ were between 2.0 μg/kg and 100 μg/kg.It was indicated that this method is easy,sensitive and can achieve a good cleanup effect.The sensitivity,accuracy and precision of the method were all acceptable,and it can meet the requirements of the multiple pesticide residues analysis.