<p>The application of dicyandiamide (DICY) covers multiple fields such as chemical, pharmaceutical, and agricultural industries, but the substance is prone to decomposition and releases highly toxic gases when heated and has the risk of explosion. Pyrolysis behaviors of DICY were measured by differential scanning calorimetry under dynamic, isothermal conditions and by adiabatic accelerated calorimetry under adiabatic conditions in this study, and based on the measured data thermal kinetics and hazards analysis were evaluated, respectively. The heat flow curves of DICY under dynamic conditions at various heating rates (1, 2, 4, and 8 ℃ min⁻¹) showed the coupling of endothermal and exothermal process at the beginning and the coupling of multi-peaks during the exothermal process. The thermal decomposition of DICY under isothermal conditions exhibited autocatalytic characteristics. The activation energy calculated using the maximum rate method was 219.7 kJ mol⁻¹, which was significantly different from dynamic test using the Kissinger method (108.5 kJ mol⁻¹); therefore, it could be assumed that reaction mechanisms have significant differences between the solid phase and the liquid phase, and the isothermal induction period was further deduced as a function of temperature. The exothermic reaction produced 58.9 mL g⁻¹ of non-condensable gas from 190.8 to 233.1&#xa0;℃ under adiabatic conditions, and the data corrected by thermal inertia showed a high possibility of uncontrolled reaction of DICY. Our research findings can certainly guide the significance for the industrial production, storage, and transportation of DICY.</p> Graphical abstract <p></p>