This paper reports on the synthesis of CuO nanoparticles (NPs) by the leaves extract of Calotropis gigantea plant in aqueous medium through green synthesis and their characterizations in terms of morphology, structure, crystallinity and catalytic properties. The synthesized CuO NPs are crystalline in nature having the average sizes in range of 30-40 nm. Green synthesized CuO NPs are utilized as effective catalyst in the thermal decomposition of ammonium perchlorate (AP) and combustion of composite solid propellants (CSPs) by measuring the thermo gravimetric analysis-differential scanning calorimetry (TGA-DSC), ignition delay and burning rate. High catalytic activity to AP decomposition and high burning rate for CSPs containing hydroxyl terminates polybutadiene (HTPB) as binder and AP as oxidizer have observed over the surface of green synthesized CuO NPs. Kinetics of thermal decomposition of AP with and without green synthesized CuO NPs was also studied by isoconversional method using isothermal TG data. (C) 2015 Elsevier B.V. All rights reserved.