It has been shown that the addition of metal oxide to potassium perchlorate gives rise to change in the thermochemical behavior of the potassium perchlorate. Some investigations on the particle sizes and materials were examined, and given data for choosing optimum weight percentage to achieve certain firing characteristics of hot-wire pyrotechnic devices. In this study, the additives (Al2O3 and Fe2O3) are found to have no effect on the crystal structure transformation, the fusion of KClO4 and the fusion of KCI. But both of the metal oxide powders exhibited a remarkable acceleration effect on the decomposition of KClO4, especially Fe2O3 does.