4,5-Bis(1H-tetrazol-5-yl)-1H-imidazole(H₃BTI) is a high-nitrogen azole compound which may be suitable as ingredient for low signal propellant and gas generator. The synthetic technology of H₃BTI was optimized with the yield of 94.6% as following: the molar ratio of 4,5-dicyanoimidazole, sodium azide and ammonium chloride, 2.2:2.2:1, solvent DMF, reaction temperature 90 ℃, and reaction time 8 h. The thermal behavior and non-isothermal decomposition kinetics of H₃BTI were studied with DSC and TG/DTG method. Results show that the kinetic parameters of thermal decomposition reaction, are the activation energy and pre-exponential factor are 197.62 kJ·mol^-1 and 16.16, respectively, and the critical temperature of thermal explosion of H₃BTI is 556.38 K, which indicates that H₃BTI has better thermal stability than that of RDX, and activation entropy, activation enthalpy and activation Gibbs free energy of the thermal decomposition are 35.72 J·mol^-1·K^-1, 193.66 kJ·mol^-1 and 173.33 kJ·mol^-1, respectively.