Abstract: The decomposition kinetics of three kinds of ablative materials is studied by means of thermogravimetric analysis TGA. The direct-solution method and difference method are applied to treat TGdata in order to derive the kinetic parameters from thermal analysis curves. By checking the experimental technique with CaCO₃ samples of known decomposition kinetic parameters, it is found that the results obtained by the present research are in good agreement with those from the literature. The decomposition kinetic parameters of three kinds of ablative materials are determined by using both the direct-solution method and difference method.