Thermal decomposition behaviors and thermal properties of diaminoazofurazan (DAAzF) and diaminoazoxyfurazan (DAAF) were studied by DSC with heating rate 2.5 ℃·min^-1, 5 ℃·min^-1, 10 ℃·min^-1 and 20 ℃·min^-1, TG /DTG at heating rate 10 ℃·min^-1, VST and thermal explosion test. The values of average activation energy of DAAzF and DAAF calculated by kissenger′s equation and Ozawa′s equation are 333.3 kJ·mol^-1, 219.3 kJ·mol^-1 with pre-exponential factors (lnA) 67.535 s^-1 and 49.230 s^-1 respectively. Thermal stability parameters of DAAzF and DAAF are shown respectively : VST: 0.26 mL·g^-1/100 ℃/48 h, 1.95 mL·g^-1/100 ℃/48 h; Loss of weight：0.08%/100 ℃/48 h, 0.47%/100 ℃/48 h; thermal explosion temperatures for 5 and 1000 seconds delay are 375 ℃ and 279.5 ℃ for DAAzF, 220 ℃ and 222.5 ℃ for DAAF respectively. These results make clear that DAAzF and DAAF have good thermal stability and the thermal stability of DAAzF is superior to that of DAAF. Sensitivity tests indicated that DAAzF and DAAF are insensitive to impact , friction and electrostatic spark. Average particle size diameters of DAAzF and DAAF were less than 10 μm analysed by LS Laser Particle Size Analyzer.