The thermal decomposition of poly(3-difluoroaminomethyl-3-methyloxetane) (PDFAMO) with an average molecular weight of about 6000 was investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The kinetics of thermolysis were studied by a model-free method. The thermal decomposition of PDFAMO occurred in a two-stage process. The first stage was mainly due to elimination of HF and had an activation energy of 110-120 kJmol(-1). The second stage was due to degradation of the polymer chain. The Fourier transform infrared (FTIR) spectra of the degradation residues showed that the difluoroamino groups decomposed in a two-step HF loss at different temperatures. The remaining monofluoroimino groups produced by the incomplete elimination of HF were responsible for the two-stage thermolysis process. The compatibility of PDFAMO with some energetic components and inert materials used in polymer-bonded explosives (PBXs) and solid propellants was studied by DSC. It was concluded that the binary systems of PDFAMO with cyclotrimethylenetrinitramine (RDX), 2,4,6-trinitrotoluene (TNT), 2,4-dinitroanisole (DNAN), pentaerythritol tetranitrate (PETN), ammonium perchlorate (AP), aluminum powder (Al), aluminum oxide (Al2O3) and 1,3-diethyl-1,3-diphenyl urea (C-1) were compatible, whereas the systems of PDFAMO with lead carbonate (PbCO3) and 2-nitrodiphenylamine (NDPA) were slightly sensitized. The systems with cyclotetramethylenetetranitro-amine (HMX), hexanitrohexaazaisowurtzitane (CL-20), 3-nitro-1,2,4-triazol-5-one (NTO), ammonium nitrate (AN), magnesium powder (Mg), boron powder (B), carbon black (C.B.), diphenylamine (DPA), and p-nitro-N-methylamine (PNMA) were incompatible. The results of compatibility studies fully supported the suggested thermal decomposition mechanism of PDFAMO.