Abstract: A hybrid precursor containing borazine and perhydropolysilazane was synthesized and characterized, and used to produce three-dimensional carbon fiber reinforced nitride matrix composites (3D Cf /Nitrides) through vacuum infiltration of the precursor followed by pyrolysis under inert atmosphere. The oxidation resistance and ablation behavior of the Cf/Nitrides were studied. Results showed that there were several bonds such as B-N, B-H, Si-N, Si-H and N-H in the hybrid precursor and the as-formed matrix had a good oxidation resistance. The matrix weight did not change distinctly when the temperature was increased from room temperature to 1 000 ℃. The surface of the ablated composites was flat and the nitride matrix had a much better ablation resistance than did the carbon fibers.