Micro-scale combustion calorimetry (MCC) and thermogravimetric analysis coupled with Fourier transform infrared spectrometer (TG-FTIR) methods were applied to investigate the combustion behavior of flue-cured, burley and oriental tobaccos, as well as the gas phase products of their cigarette samples under smoldering conditions. The results indicated that the combustion temperature of the test tobaccos ranged mainly from 150 to 600 °C, and burley and oriental tobacco were more combustible than flue-cured tobacco. The gas phase products, CO₂, CO, H₂O and carbonyl compounds, were mainly formed in the range of 100-800 °C. Under 150 °C, H₂O and carbonyl compounds were the major gas phase products; when temperature was above 150 °C, CO₂ increased rapidly; over 300 °C, the formation of CO became obvious, oxygen concentration affected the formation of CO₂, CO, H₂O and carbonyl compounds to different extents.