Statistical evolution of microvoids in a particle-filled polymer under plate impact is theoretically studied. Based on the constitutive equations of the material recently obtained by the authors, the velocity of the propagation of one-dimensional strain wave caused by the plate impact is analyzed, and the evolution of the microdamage is calculated. It is shown that the microvoid evolution is influenced by several factors, such as particle size-dispersity, average radius of particles, and the adhesive energy of the interface. The numerical results show that there is a sensitive crest of the impact velocity for microvoid evolution. If the impact velocity reaches the critical value corresponding to the peak value of the crest, the microvoids accumulation will increase rapidly, and it may lead to the dynamic failure of the material.