Carbon/carbon （C/C） composites are prone to oxidation above 370 ℃， which restricts their further utilization in aerospace and military applications. Hence， enhancing the ablation resistance of C/C composites holds paramount significance. This research utilized citric acid， ethylene glycol， and metal salt solutions as precursors to fabricate C/C-Hf _x Zr_{1- x} C composite materials with a density ranging from 2.00 g/cm³ to 2.10 g/cm³ employing the precursor impregnation and pyrolysis （PIP） and ceramicization. The effect of different Hf/Zr ratios on the ablation resistance of C/C-Hf _x Zr_{1- x} C composites is investigated. The results indicate that Hf _x Zr_{1- x} C manifests as a solid solution ceramic. With the increase in Hf proportion， the ablation rate of C/C-Hf _x Zr_{1- x} C composites first decreases and then increases. Among them， C/C-Hf_0.5Zr_0.5C shows superior ablation resistance. When ablated for 120 s at a heat flux density of 3.5 MW/m²， the mass ablation rate and linear ablation rate of C/C-Hf_0.5Zr_0.5C are 1.39×10^-2 g/s and 7.49×10^-3 mm/s， respectively. This superiority can be attributed to the strong adhesion of the oxidation product HfO₂-ZrO₂ to the fiber and matrix in C/C-Hf_0.5Zr_0.5C， thereby mitigating mechanical erosion on the fiber and matrix. Simultaneously， the lower melting point of the HfO₂-ZrO₂ mixture facilitates the formation of a molten mixture of HfO₂-ZrO₂， consequently reducing the oxygen permeability of the oxide layer.