Detailed analysis of the dispersion of ethylene and propylene copolymer components in high-impact polypropylene particles was performed by the morphological observation, pore volume analysis, and microscopic Fourier transform infrared spectroscopy of SPring-8. The results of the morphological observation and pore volume distribution suggest that copolymer components were formed in particles in such a manner as to fill the gaps of fine homopolypropylene particles. The results of the analysis by microscopic Fourier transform infrared spectroscopy were that the distribution of the amount of ethylene in the particles was homogeneous and indicated that copolymer components were dispersed uniformly within the particles. Moreover, spots with high amounts of ethylene were formed on the particle surface, and when voids existed within the particle, spots with high amounts of ethylene were also formed on the void surface. The structure of the copolymer components existing locally on the surface was practically similar to the structure of the copolymer components within the particles. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 632-638, 2011