The catalytic effect of catocene was studied on the kinetic of thermal decomposition of NTO (3-Nitro-1, 2, 4-triazol-5-one) and NTO/TNT (Trinitrotoluene) explosives. NTO is an insensitive explosive and can use as an alternative of many nitramine explosives and thus composite explosive of NTO/TNT shows the properties of an insensitive explosive. FT-IR spectra show the minor changes in molecular bonds of NTO and TNT with addition of catocene. SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy) analysis indicates the morphology of prepared samples and presence of catalyst in the matrix of samples. TG/DSC (Thermal Gravimetry/Differential Scanning Calorimetery) method is used to study the thermal behaviour of NTO and NTO/TNT in absence and presence of 3% wt. of catocene. A decrease 5 oC in exothermic peak temperature of DSC curves and a decrease 50 kJ/mol in activation energy (Ea) of thermal decomposition reactions of NTO and NTO/TNT are seen in presence of catocene. The activation energies are calculated by model-free methods of Ozawa–Flynn–Wall (OFW), and Kissinger–Akahira–Sunose (KAS). Tests of sensitivity to impact, friction, and electric discharge show the stability of NTO and NTO/TNT against external stimuli in the presence of catalyst.