The silicone rubber (SR) nanocomposites have been successfully prepared via the in situ hydrosilylation reaction in the presence of pristine ZnO and vinyl silane modified ZnO ( SiVi@ ZnO ) nanoparticles. The structure of the pristine ZnO and SiVi @ ZnO nanoparticles were analyzed by the Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The morphology, thermal stabilities, mechanical properties and thermal conductivity of the nanocomposites were also investigated. The results showed that the SiVi @ ZnO nanoparticles exhibit a better dispersion in the silicone rubber than the pristine ZnO nanoparticles. The corresponding silicone rubber/ SiVi @ ZnO (SR/ SiVi @ ZnO ) nanocomposites showed higher mechanical properties and thermal conductivity due to the better dispersion in silicone rubber matrix.