Thermal technique has been widely used for thermal hazard analysis of chemical substances and safety management of chemical processes. In this paper, thermal hazard of cumene hydroperoxide with cumene solvent is experimentally analyzed with DSC, Calve-type heat flux calorimeter and high sensitivity thermal activity monitor, and the thermal decomposition mechanism is investigated with Raman spectroscopic analysis. Further, thermal risk diagram of chemical process is shown and layer of protection analysis is described.