Abstract: The thermogravimetry analysis was used to study the effects of solvent extract on pyrolytic decomposition and combustion of cut tobacco. The results indicated that the thermal chemical properties of hexane and ethyl acetate extraction were much more like the ones of normal tobacco and other than the ones of methanol extraction. By calculation, the order of combustion index was S_n(normal tobacco)>S_n(hexane extracting)>S_n(ethyl acetate extracting)>S_n(methanol extracting).