Effects of different silanization followed via the sol-gel growing of silica nanoparticles (SiO2) onto carbon fibers (CFs) on interfacial strength of silicone resin composites were investigated systematically. CFs were grafted with 3-aminopropyltriethoxysilane (APS) at different conditions to introduce amino groups (CF-NH2) or ethoxy groups (CF-Siloxane) for improving interfacial interaction between CFs and SiO2. Experimental results indicated that SiO2 was grown onto different functionalized CFs successfully, which enhanced the wettability owing to the increases of fiber polarity and surface roughness. Interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) of SiO2 modified CFs composites enhanced significantly, especially for CF-Siloxane grafted with SiO2 (CF-Siloxane-SiO2), increasing 46.79% in ILSS and 39.61% in IFSS. Additionally, the introduced Si-O-C bonds increased hydrothermal aging resistance of the resulting composites greatly. (C) 2018 Elsevier B.V. All rights reserved.