Fe2O3 nanoparticles with diameter 3~5 um were encapsulated in polymer latexparticles. The size of the composite microspheres was 80 um. From IR spectra, the changesof absorption band on carbonyl groups indicated the strong interaction between Fe2O3 and thesurface groups of seed latex particles. According to Mdssbauer spectra, we were sure aboutthe core-shell structure of the inlayer microspheres from the changes of the electron densityand symmetry of the chemical environment around Fe2O3.