The properties of the interface have a significant impact on the application of silicone rubber (SR) composite coating fillers with carbon fiber (CF). The one-step growth of silica nanoparticles on the fiber surface was investigated in terms of the mechanical, electrical, and thermal properties of the CF/SR composite coatings. The results showed that the tensile strength and elongation of the composite with modified fibers were 7.13 ± 0.44 MPa and 690.40 ± 37.04 %, which were 20.44 % and 23.22 % higher than those with unmodified CFs, respectively. The improvement in interfacial adhesion by silica modification effectively disperses stress and avoids stress concentration. Additionally, the introduction of the low-dielectric material SiO2 and the reduction of the interfacial polarization enhanced the wave-transmission properties and weakened the electromagnetic wave-shielding properties of the composites. Meanwhile, the silica modification maintained the antistatic properties of the coatings at room and high temperatures, as well as before and after bending. The weight loss of the composites with modified fibers was lower than that of the composites with unmodified fibers, while the thermal conductivity was higher because of the stable structure of the Si-O-Si bonds and interfacial adhesion. This work provides a simple way to enhance the thermal resistance, thermal conductivity, mechanical and wave-transmission properties, and preserve the antistatic properties as well as the flexibility of CF/SR composite coatings.