A new high-energy organic ammonium salt 4, 4′-azo-1H-1, 2, 4-triazol-5-one ammonium salt (AZTO·H₂O) was synthesized via potassium permanganate oxidation using 4-amino-1, 2, 4-triazol -5-one (ATO) as starting material. The thermal behaviors of AZTO·H₂O was studied by differential scanning calorimetry. The kinetic parameters of non-isothermal exothermic decomposition reaction were calculated by Kissinger method and Ozawa method. Results show that the decomposition heat, apparent activation energy and pre-exponential factor of AZTO·H₂O are 247.46 kJ·mol^-1, 177.80 kJ·mol^-1 and 10^15.74 s^-1 respectively. The critical temperature of thermal explosion and molar heat capacity at 298.15 K for AZTO·H₂O is 233.10 ℃ and 271.45 J·mol^-1·K^-1, respectively. The adiabatic time-to-explosion is between 72.8 s and 74.7 s. The kinetic equation describing the exothermic decomposition reaction of AZTO·H₂O is $\frac{{{\rm{d}}\alpha }}{{{\rm{d}}\mathit{T}}}{\rm{ = }}\frac{{{{10}^{15.74}}}}{\beta } \times 4(1 - \alpha ){[{\rm{-ln}}(1 - \alpha )]^{\frac{3}{4}}}\exp ( - 1.774 \times {10^5}/\mathit{RT})$.