<p>In order to study the thermal hazard of n-butylethanolamine in nitration reactions, a Calvet microcalorimetry was used to measure the exothermic evolution of the two-step nitration reactions, differential scanning calorimetry (DSC) was used to measure the thermal decomposition curves of the initial materials and nitration products at different stages of the two-step nitration reaction, and the most unstable reaction system during the reaction process was determined by comparing the initial decomposition temperature. Adiabatic acceleration calorimetry was used to measure the heat release process of the most unstable materials under adiabatic conditions, and the thermal safety characteristic parameters were obtained based on the adiabatic decomposition kinetics model. Finally, the degree of danger of BuEA nitration reaction was determined by the principles of reaction risk assessment. This study provides critical safety technical guidance for the BuEA synthesis process and safety design. The result shows that the BuEA nitration reaction is a strong exothermicity reaction. The maximum temperature of a synthesis reaction (<i>MTSR</i>) is 234.12&#xa0;°C. The initial stage of the first-step nitration reaction represents the most unstable reaction system, and <i>T</i>_D24 is 57.31&#xa0;°C. According to the relationship among the <i>T</i>_P, MTSR, <i>T</i>_D24 and MTT, the degree of danger of the reaction can be divided into five levels. It is indicated that the adding rate of BuEA should be strictly controlled during the reaction process to keep the temperature rise below 57.31&#xa0;°C and prevent decomposition exotherm in the reaction system. This study is the first systematic thermal hazard assessment for BuEA nitration process, filling the research blank of thermal safety for BuNENA industrial production. It provides essential technical support for defining safe operating boundaries, optimizing feeding control, and realizing inherent safety in synthesis and engineering design.</p>