A transparent organic-inorganic epoxy/silica hybrid material was prepared by epoxy resin, functionalized-epoxy resin, which was partially functionalized by 3-aminopropyl triethoxylsilane(APTES), and highly reactive polysilcic acid (PSA), which was prepared through hydrolysis and condensation of metasilicate salt. The properties of hybrid materials such as impact strength, tensile strength, glass transition temperature (T-g), thermogravimetric temperature (TGA), and thermal effect of the hybrid materials were studied. The size of PSA particles in THF measured by dynamic light scattering technique, ranged from 10-28 nm. The results of experiment indicated that modified epoxy resin possed better roughness than that of the pure epoxy resin. The structure of the hybrid materials was characterized by FT-IR spectroscopy and (SiNMR)-Si-29 spectroscopy. (C) 2005 Springer Science + Business Media, Inc.