Dicumylperoxide (DCPO), is produced by cumene hydroperoxide (CHP) process, is utilized as an initiator for polymerization, a prevailing source of free radicals, a hardener, and a linking agent. DCPO has caused several thermalexplosionand runaway reaction accidents in reactionand storage zone in Taiwan because of its unstable reactive property. Differential scanning calorimetry (DSC) was used to determine thermokinetic parameters including 700 J g–1of heat of decomposition (ΔHd), 110 °C of exothermic onset temperature (T0), 130 kJ mol–1of activation energy (Ea), etc., and to analyze the runaway behavior of DCPO in a reactionand storage zone. To evaluate thermalexplosionof DCPO with storage equipment, solid thermalexplosion (STE) and liquid thermalexplosion (LTE) ofthermal safety software (TSS) were applied to simulate storage tank under various environmental temperatures (Te). Te exceeding the T0of DCPO can be discovered as a liquid thermalexplosion situation. DCPO was stored under room temperature without sunshine and was prohibited exceeding 67 °C of self-accelerating decomposition temperature (SADT) for a tank (radius = 1 m and height = 2 m). SADT of DCPO in a box (width, length and height = 1 m, respectively) was determined to be 60 °C. The TSS was employed to simulate the fundamental thermalexplosion behavior in a large tank or a drum. Results from curve fitting demonstrated that, even at the earlier stage of the reaction in the experiments, ambient temperature could elicit exothermic reactionsof DCPO. To curtail the extent of the risk, relevant hazard information is quite significant and must be provided in the manufacturing process.