For thermal insulation applications, carbon/carbon composites (C/CCs) are considered to be one of the most promising materials owing to their light weight, low thermal conductivity, and high temperature tolerance. In this paper, zirconium dioxide, nano-silica and alumina were introduced into carbon fiber felt/phenolic resin composites as functional materials by resin impregnation, and silica/alumina/zirconium dioxide@carbon/carbon composites (SiO₂/Al₂O₃/ZrO₂@C/CCs) with excellent thermal insulation properties were prepared. The thermal conductivity of SiO₂/Al₂O₃/ZrO₂@C/CCs at 500 ℃ is only 0.135 W/(m·K). The effects of different component ratios on thermal insulation properties were discussed, and the surface morphology, mechanical properties and thermal insulation properties of carbon/carbon composites containing different metal oxides were compared and analyzed. Compared with the carbon/carbon composites without nano-inorganic materials, the results show that not only the thermal insulation performance of the composites but also the thermal stability are extremely improved. Under the synergistic action of SiO₂, Al₂O₃ and ZrO₂, the improvement effect is the most obvious, which is more conducive to the utilization of the composites in high temperature environment.