In order to study the thermal decomposition properties of the characteristic groups of 3，4-Dinitrofurazanylfuroxan （DNTF）， differential scanning calorimetry （DSC） and fast scanning Fourier transform infrared spectroscopy （FTIR）were adopted to study the thermal decomposition properties of DNTF in condensed phase. The changes of characteristic groups of DNTF were studied by using FTIR technology at three different heating rates of 2.5， 5.0， 10 ℃·min^-1. The thermal decomposition kinetic parameters of C─NO₂， furazan ring， and furoxan ring of DNTF were calculated by the Coats-Redfern method. The thermal decomposition mechanism of DNTF was inferred based on the thermal decomposition properties of the characteristic group of DNTF. The results show that the thermal decomposition of DNTF is controlled by the three-dimensional diffusion mechanism. The reactivity of groups in DNTF molecule is nitro>furoxan ring>furazan ring. With the increase of heating rate， the reactivity of each group shows an increasing trend. It is speculated that the thermal decomposition process is that C─NO₂ breaks first， and then the C─C bond connecting furuzan and furoxan ring breaks， and finally the N─O bond in furazan ring and furoxan ring breaks. The furoxan ring decomposes faster than furazan ring.