In order to study the thermal decomposition behavior of 2,4,6-trinitro-3,5-difluorophenol, the non-isothermal decomposition reaction kinetics of 2,4,6-trinitro-3,5-difluorophenol was studied by thermogravimetric-differential thermal analysis (TG-DTA). TG-DTA experiments were carried out under dynamic nitrogen atmosphere of 30 mL·min^-1 with heating rates of 5, 10, 15 K·min^-1 and 20 K·min^-1, respectively. The thermal decomposition parameters of 2,4,6-trinitro-3,5-difluorophenol, such as activation energy (E) and pre-exponential factor (A), were calculated by F-W-O, Doyle, Kissinger and Satava- Sestak methods, respectively. Results show that the compound converts into molten state first and then decompose along with rapidly exothermic. The average apparent activation energy of thermal decomposition was calculated to be 122.65 kJ·mol^-1 with a pre-exponential factor of 1.37×10¹³ min^-1, and the integral form of reaction mechanism function is g(α)=α^1/2. The calculated activation enthalpy () in the thermal decomposition process according to its activation energy and pre-exponential factor is 123.06 kJ·mol^-1, the activation entropy () is 121.46 J·mol^-1·K^-1, and the Gibbs free energy of activation () is 62.98 kJ·mol^-1.