A method of liquid chromatography mass spectrometry（LC-MS） was used to analyze the chemical weapon related compounds in the aqueous decontamination effluent samples of the 42nd Official Organization for the Prohibition Chemical Weapons（OPCW） Proficiency Test.Firstly，the blank sample，control sample and simulated sample were distinguished by HPLC-Q-TOF MS from the three aqueous decontamination effluent samples，then three chemical weapon related compounds were preliminarily found out in simulated sample.Finally，2-hydroxyethyl vinyl sulfide，divinyl sulfone and 1,2-bis（2-hydroxyethylthio）ethane in the simulated sample were identified simultaneously by UPLC-QQQ MS.The buffer agents，fragmentor voltages and fragmentation pathway were discussed adequately.The results obtained were in accordance with the list of spiking chemicals provided by the laboratory of OPCW.The method could provide a reference for the analysis on the decontamination products of sulfur mustard.