By means of the wet chemical Surface modification, the surface of Fe2O3 was modified by vinyltrimethoxysilane (VTMS). Infrared spectroscopy (IR) was used to investigate the structure of the modified Fe2O3, and the result showed that VTMS has been attached onto the surface of Fe2O3. Effect of VTMS concentration on the active index of the modified Fe2O3 was also studied, and the result indicated that the active index of the modified Fe2O3 increases with the increase of VTMS concentration and the optimal concentration of VTMS is 12 wt %. The effect of the modified Fe2O3 on the tear strength of silicone rubber before and after aging was studied and it was found that in comparison with the unmodified Fe2O3 the addition of the modified Fe2O3 results in the significant increase of the tear strength before ageing because of the increase of the crosslinking density of silicone rubber. The tear strength of silicone rubber filled with the modified Fe2O3 after ageing is higher than that with the unmodified Fe2O3 indicating that the modification of Fe2O3 can improve the heat-resistance of silicone rubber Owing to the fine dispersion of the modified Fe2O3 in Silicone rubber. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113:3202-3206,2009