As one of the energy storing elements of explosively-driven flux compression generators, the pulsed capacitor was required to discharge only once, such as explosively-driven flux compression generators. Therefore, it provided a possibility to make the pulsed capacitor working in overstress. Compared with the overstressing capacitor, the pulsed capacitor has several advantages, such as small volume and light weight. So it could be used as a current driver to miniaturize explosively-driven flux compression generators. The overstress characteristics of metalized polypropylene pulse capacitor (MPP capacitor) were investigated at different temperatures. Experimental results show that the energy storage density is 1.8 times of the rated energy storage density at the temperature of-45~60℃, and in this condition, the oneside lower confidence limit of reliability is 0.9 if the confidence level is 0.95.