Abstract: A method of high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) for simultaneous determination of 23 pesticides in traditional Chinese medicine Paeoniae radix Alba was developed. P.radix was extracted with acetonitrile,and then purified using a preliminary sample treatment step based on primary-secondary amine (PSA) dispersive solid-phase extraction.Limits of quantification (LOQ) were between 0.75-12.17 μ g/kg.Recovery between 70% and 120% were obtained for all pesticides at 0.01 and 0.1 mg/kg levels,except for polar pesticides such as thiamethoxam and imidacloprid.This method is accurate,reproducible and has good cleanup effect.It could be applied in pesticide residue analysis in P.Radix.