In this paper, the functionalized nanosilica was prepared via covalent modification and used as effective nanofillers to reinforce silicone rubber matrix. The influence of functionalized nanosilica on the mechanical property of PVMQ was examined. The microstructures of the nanocomposites were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. As the nanosilica loading reaches up to 90 wt%, the tensile strength of functionalized nanosilica/PVMQ rubber nanocomposites can reach the maximum values (3.67 MPa). It was noteworthy that the functionalized nanosilica not only could be homogeneously dispersed and incorporated into the polymeric matrix as fillers but also could be effectively improved the mechanical property of the silicone rubber.