Abstract: To establish an analytical method for odor components in environmental tobacco smoke (ETS), a thermal desorption combined with multidimensional gas chromatography-mass spectrometry/olfactometry (ATD-MDGC-MS/O) analytical system was developed for the first time. The simulated ETS in a chamber was analyzed by the ATD-MDGC-MS/O method after being sampled and enriched by the sampling tube, and the dilution factors of the compounds were determined by the aromatic dilution method. The developed method was applied to the analysis of ETS odor components of cigarettes of different types. The results showed that: 1) The olfactory evaluation results of ETS odor of cigarettes of different types differed. 2) A total of 66 odor components and their odor characteristics in ETS were analyzed and determined, and different components had different odor characteristics. 3) It was clear that the major odor components in ETS include trimethylamine, N, N-dimethylethylamine, acetic acid, 3-methylbutyric acid, 3-vinylpyridine, 3-methylvaleric acid, methyl cyclopentenone, guaiacol, maltol, etc. This method has the advantages of simple operation, high sensitivity and accurate results, and provides technical support for further study of odor components in ETS.