To study the thermal decomposition behavior of 2，2-azobi［4，5-bis（tetrazole-5-yl）］-1，2，3-triazole （NL24）， the structure， morphology and thermal decomposition characteristics of NL24 were studied by means of scanning electron microscopy， thermogravimetric analyzer， differential scanning calorimeter and thermogravimetric infrared mass spectrometry. The kinetic parameters such as apparent activation energy and pre-exponential factor were calculated by Kissinger， Ozawa and ?atava-?esták method， and the thermal decomposition mechanism of NL24 was speculated. Results show that NL24 has two main weight loss stages at the heating rate of 10 ℃·min-1 . The first weight loss stage occurs at about 180 ℃， which belongs to the volatile endothermal process of dimethyl sulfoxide. The violent thermal decomposition of NL24 occurs at the second weight loss stage between 270 ℃ and 300 ℃， which has not only rapid gas generation rate， but also belongs to autocatalytic reaction. The main gaseous products are N2， HCN， HN3， etc. The apparent activation energy and pre-exponential factor of the decomposition process are 174.69 kJ·mol-1 and 1016.60 s-1 ， respectively. The reaction model of thermal decomposition stage of NL24 is random nucleation and subsequent growth.