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With a view to improve the affinity of silica particles for the polymer matrix, a new type of polyimide/silica(PI/SiO2) hybrid composite films has been successfully prepared using the polymer-modified silica gels. First, poly(maleic anhydride-co-styrene)/silica[P(MA-ST)/SiO2], polymer-modified silica gels, were prepared by the condensation reaction of the surface hydroxyl group of silica gel with a polymeric coupling agent, P(MA-ST)–trimethoxysilane. Then, PI/SiO2 hybrid films of different silica contents were obtained by the blending of polymer-modified silica gels with poly(amic acid)(PAA) from pyromellitic dianhydride(PMDA) and 4,4′-diaminodiphenyl ether(ODA) in N-methyl-2-pyrrolidinone(NMP). The decomposition temperature at 5 wt% loss(Td5) of the hybrid films, as measured by thermogravimetric analyses(TGA), increased with the increasing P(MA-ST)/SiO2 content within the measured range. The PI/SiO2 hybrid films with ca. 5 wt% of modified-silica exhibited balanced mechanical properties, whereas the hybrid films with higher silica contents had reduced mechanical properties, as confirmed by the scanning electron micrographs(SEM) observation. [ABSTRACT FROM AUTHOR]