With the development of hypersonic weapons, their harsh thermal environment making it crucial to enhance the comprehensive performance of thermal protection materials. In this paper, Kevlar nanofibers (KNFs) were coated with nano-silica through in-situ growth on their surface to obtain KNFs@SiO2. The influence of γ-aminopropyltriethoxysilane (KH550) modified KNFs@SiO2 on the ablation resistance and mechanical properties of ethylene propylene diene monomer (EPDM) was investigated. The results showed that compared to EPDM, the tensile strength and elongation at break of the KNFs@SiO2/EPDM composite filled with 5 parts of KH550 modified KNFs@SiO2 (KKNFs@SiO2) increased by 235.5% and 65.4%, respectively, while the linear ablation rate and mass ablation rate decreased by 69.9% and 47.6%, respectively.