Phenolic compounds exist widely in the influents and effluents of sewage treatment plants (STPs) and most are un-regulated.In this study,a gas chromatography-mass spectrometry (GC-MS) method for the simultaneous analysis of 50 phenolic compounds in wastewater was developed.Deconvolution technology was used to identify contaminants that are covered by co-extracted materials.A mass spectral library containing all 50 silylated phenolic compounds was first established and used for deconvolution.Twelve typical phenolic compounds were selected to optimize the sample preparation procedures.Solid-phase extraction using a C18 cartridge coupled with an HLB cartridge was used for pre-concentration and dichloromethane was used for elution.The solutes were derivatized and analyzed by GC-MS.The blank and matrix spike recoveries ranged from 57.46% to 136.4% and 47.87% to 114.8%,respectively.Method detection limits ranged from 3.64 to 97.64 ng L–1.The relative standard deviations of all the recovery experiments were lower than 13.6%.The instrument limits of quantification ranged from 0.7 to 87.7 pg.The method has been applied to analyze the influents and effluents of 5 Chinese STPs.Except for regulated phenolic compounds (phenol and 2,4,6-trichlorophenol),three un-regulated phenolic compounds,including 2-chlorophenol,2,5-dichlorophenol and 2,4-dichloro3-ethyl-6-nitrophenol were identified in the effluent wastewater.The detected concentrations of un-regulated phenolic compounds could possibly cause environmental effects,indicating that immediate attention is required to prevent complications.