Co nanoparticles supported on carbon nanotubes (CNTs) were prepared by microwave-assisted heating of the hydrazine reduction in ethylene glycol (EG). The Co/CNT nanocomposites prepared by the microwave-irradiation method (MIM-Co/CNTs) were characterized by XRD, SEM, EDS, and BET. It was found that MIM-Co/CNTs had compact coating, high cobalt loading, and large BET surface area. The obtained products for the thermal decomposition of ammonium perchlorate (AP) were investigated by DTA. The catalytic activity of MIM-Co/CNTs was better than that Of pure Co nanoparticles and Co/CNT nanocomposites by water-bath method (WBM-Co/CNTs). The addition of 5 wt.-% MIM-Co/CNTs decreased the high decomposition temperature of AP by 174.05 degrees C and increased the total DTA heat release by 0.799 kJ g(-1).