Abstract: A method for simultaneously selectively determining seven benzenes(benzene,toluene,ethyl benzene,p-xylene,m-xylene,o-xylene and styrene) in mainstream cigarette smoke by cold trap and gas chromatography-mass spectrometry(GC/MS) was developed,and the deliveries of the said analytes in mainstream smoke of five cigarette samples of different brands under intense smoking regime and ISO smoking regime were investigated.The benzenes in the gas phase of mainstream cigarette smoke were trapped with cold methanol containing o-xylene-d₁₀(internal standard),and analyzed by GC/MS under selected ion monitoring mode.The results showed that:1) The limit of detection and limit of quantification for the seven benzenes were 0.006 and 0.018 μg/cig,respectively.The recoveries ranged from 95.8% to 110.1% with the relative standard deviations(RSDs) of 1.1% to 4.6%.The deliveries of the seven analytes in gas phase of mainstream cigarette smoke under intense smoking regime roughly doubled those under ISO smoking regime.This method is suitable for analyzing the seven benzenes in gas phase of mainstream cigarette smoke.