SiO2 / PF composite materials with HGB content of 0,3%,5%,10% respectively were prepared. The effects of HGB content on the density, thermal physical properties, ablation resistance, thermal expansion properties, mechanical properties were investigated. The results show that, HGB addtion can reduce the SiO2 / PF density, improve the heat resistance, ablation resistance and mechanical properties. When the HGB content is 5%, the system density is 1． 634 g/ cm3. At 23℃ cp increased from 1.062 to 1.137 J/ (g·K), 950℃, quality retention rate is 82． 08%. The linear ablation rate and mass ablation rate is 91 μm / s and 66． 9 μg/ s,about 35.9% and 20.1% lower than that of SiO2 / PF. The tensile strength, the bending strength and the shear strength are increased by 12.86%, 21.50% and 7． 80%.