Ablative thermal protection material is usually applied as the heat shield of high speed reentry vehicle. The mechanical properties， thermophysical properties and ablation properties of two kinds of honeycomb enhanced silica-based low density ablative thermal protection materials are investigated， with the analysis of the ablation mechanism. The results show that the tensile strength increases with the density， with the same tensile modulus. The thermal insulation performance parameters of the two kinds of materials are both relatively low. The linear ablation rates of the two kinds of materials are relatively low under different heat flux in the arc wind tunnel， and some materials expand slightly under certain conditions. The back temperature of two materials are relatively low， with a good surface morphology. The research shows that the materials meet the target requirements with a wide range of applications.