An effective liquid chromatography-tandem mass spectrometric（HPLC-MS/MS） method was developed for the determination of ethyl carbamate in cigarette mainstream smoke.The ethyl carbamate in cigarette mainstream smoke was trapped with Cambridge filter,and then extracted with an oscillation using ethanol as extraction solvent.Influences of elution solvent type,solvent consumption and different polarity solid-phase extractions on purification efficiency of the target analyte were discussed.Under the optimal conditions,the calibration curve of the method was in the range of 6-720 μg/L with correlation coefficient（r2） of 0.999 9.The relative standard deviations（RSDs） of intra-day and inter-day were less than 6% and 5%,respectively.The spiked average recoveries ranged from 93.7% to 99.8%,and the limit of quantitation（LOQ） was 0.26 ng/cig.With the advantages of accurancy,sensitivity,good reproducibility and low solvent consumption,the method was suitable for the determination of ethyl carbamate in cigarette mainstream smoke.