Silicon doped CH foams are prepared via a thermally induced phase-inversion technique. With poly(4-methyl-1-pentene) as the foam skeleton material, durene/naphthalene as the solvent/nonsolvent system, and SiO2 as the doping materials, Si doped CH polymer foams with density of 25 to 80 mg/cm3 is successfully prepared, and the mass content of Si is <30%. This paper presents the fabrication procedures of Si doped CH polymer foams. The parameters that influence the properties of the foam products are discussed in detail. The thermal stability and structure of Si doped CH foams are also discussed.