Ionic liquids are molten salts that possess excellent chemical and thermal stability. Due to their inherent qualities in green chemistry, ionic liquids have been identified as potential substitutes for traditional organic solvents. These useful physical and chemical properties lead to some promising applications in fields such as building polymer engineering alternative materials and renewable energy technologies. Although they are classified as green solvents, these new solvents exist in a high-temperature environment, which is related to thermochemical reactivity and safety; there are few related studies. To analyze the possible high-temperature application environment of ionic liquids in the future, we analyzed the new ionic liquid 1-Benzyl-3-methylimidILlium bis (trifluoromethylsulfonyl) imide ([BZMIM][TF2N]), which lacks thermal analysis basis. This study used thermogravimetric analysis as the basis of the reaction model. We calculated the thermal hazard, kinetics, and parameter analysis of the reaction characterized by experimental thermal analysis data. The reaction model can be used to construct the actual temperature change calculation. The results show that [BZMIM][TF2N] will enter a runaway reaction when the temperature exceeds 270 °C. When operating [BZMIM][TF2N] at high temperatures, attention should be paid to the possibility of thermal hazards caused by its self-decomposition reaction.