Abstract: In order to investigate the pyrolysis properties of tobacco lamina and stem, their pyrolysis processes in an oxidative atmosphere were studied with thermogravimetric analysis, and the kinetic analysis of each thermal weight loss phase after the evaporation of adsorbed water was conducted with Coats-Redfern and Malek methods. The results showed that:1) The pyrolysis process of lamina mainly included five different phases, while nine different phases were observed in the pyrolysis process of stem. 2) At the adsorbed water evaporation phase and thermo-oxidative degradation phase of biological polymer, lamina and stem had similar weight loss rate, but the weight change rates at the other phases were obviously different. 3) Most of thermal weight loss phases of lamina and stem could be simulated by F1 kinetic model. Comparing with lamina, stem featured higher kinetic parameters at most phases, but thermo-oxidative degradation phase when their activation energies were similar.