Ultra-high temperature ceramic matrix composite material is a new type of thermal structure/function integrated material that combines the performance advantages of metal materials, ceramic materials and carbon materials. It has high temperature resistance, low density, high specific strength, high specific modulus, oxidation resistance, ablation resistance, insensitivity to cracks, no catastrophic damage, etc., It has a wide range of applications in machinery, aerospace, nuclear, energy and other fields. The in-situ synthesis of refractory metal carbides (ZrC, HfC, TaC) in C/SiC composites can significantly improve their ablation resistance.The main mechanisms can be summarized as inhibiting oxidation, enhancing the erosion resistance of the substrate and making up for the defects after ablation.