Comparative studies on corrosion protection properties of polyimide-silica-clay composites were studied in this article. A series of polyimide-silica (PIS), polyimide-clay (PIC), and polyimide-silica-clay composites (PISC) materials, consisting of an organo-soluble polyimide (ODA-BSAA) matrix, inorganic silica particles prepared through the sol-gel reaction of tetraethyl orthosilicate (TEOS) and dispersed nanolayers of inorganic montmorillonite clay, were successfully prepared by solution dispersion technique. Then, all samples were characterized by FTIR, powder X-ray diffraction patterns, transmission electron microscopy, and Si-29 solid-state NMR. The main focus of this article is the comparison of the corrosion protection properties of PIS, PIC, and PISC composite materials. Normally, the aspect ratio of clay is higher than silica. Superior dispersion of clay platelets into a polymer matrix may effectively increase the length of diffusion pathways for oxygen and water. The effects of the materials composition on the corrosion protection performance, gas barrier, and optical properties, in the form of both coating and film, were also studied by electrochemical corrosion measurements (e.g., corrosion potential, polarization resistance, corrosion current, and impedance spectroscopy), gas permeability analysis, and UV-visible transmission spectroscopy. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 548-557, 2011