Rugate filter is a special inhomogeneous optical coating. The graded refractive-index profile makes it have better optical and mechanical properties than conventional homogeneous optical coating. The graded refractive index SiOx (0≤x≤2) coating materials with precisely controlled refractive index ranging from 2.74 to 1.59 (λ=1550 nm) are deposited by tuning its oxidation degree in reactive magnetron sputtering. Then high quality SiOx infrared rugate filters are successfully designed and fabricated by choosing proper refractive index amplitude apodization function and introducing refractive index matching layer on the interface, which provides a practical and economical technique for industrial fabrication of rugate filters.