Abstract: The thermogravimetric analysis of several domestic tobacco samples was conducted. The results showed that:1) from room temperature to 500℃, under the non-isothermal conditions, tobacco goes through 4 stages, i.e. loss of adsorbed water and crystal water, volatilization and decomposition of small molecule compounds, pyrolysis of macromolecular compounds, and coking, the pyrolysis takes place mianly between 220℃ and 410℃; 2) flue-cured, burley and oriental tobacco leaves are recognizable by their differential thermogravimetric (DTG) curves; 3) thermogravimetric character of expanded tobacco is similar to that of reconstituted tobacco, it is significantly different from that of expanded cut stem; 4) there are some differences between DTG curves of C3F of cultivar K326 grown in Yunnan, Hunan, Hubei, Henan and Fujian Provinces in 2007, mainly in their weight-loss at different stages.