Characteristics of phase transition, thermal behavior and kinetics of non-isothermal decomposition of 4′4-bis-1, 2, 4-triazole (BTz) were studied using in-situ X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetry (TG). The results show that, at around 170 ℃, the solid-solid phase transition is detected at a heating rate of 10 ℃·mol^-1, followed by the melting starting at about 270 ℃ and the peak temperature of thermal decomposition of BTz is 290.0 ℃. The phase transition of BTz is reversible according to the result of in-situ XRD and DSC. Based on the detected decomposition temperatures at various heating rates (β), the decomposition temperature at the heating rate approach to zero was derived with the value T_p0=256.3 ℃. By means of Kissinger method and Ozawa method, the calculated activation energies (E_a) are 224.7 kJ·mol^-1 and 222.4 kJ·mol^-1, and pre-exponential factors (A) are 6.31E+20 s^-1 and 3.98E+20 s^-1, respectively.