Polyimide/silica hybrid materials were prepared via a novel sol-gel route using silicic acid oligomer (SAO) extracted from water glass. The decomposition temperatures of the hybrid samples were higher than pure polyimide. The transparency of the hybrid films could be maintained at up to 40 wt.-% silica content with the addition of gamma-aminopropyltriethoxysilane (APTES). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results confirmed the formation and dispersion of nanometer-scale size of inorganic particles within polyimide matrix with APTES. The coefficients of thermal expansion (CTEs) of the hybrid films were lower than pure polyimide and decreased with the increasing content of silica.