B₄C induced SiC/SiC composites were prepared by prepreg-melt infiltration method. Oxidation behavior and self-healing mechanisms of B₄C modified SiC matrix was studied at different oxidized temperatures. Self-healing behavior of the SiC–B₄C matrix has also been noticed, cracks were filled by the oxidation products at the high temperatures. Moreover, the oxidation resistance of the SiC/SiC–B₄C composites at elevated temperature was also investigated. The results demonstrate that when the oxidation temperature is 700 ℃, B₂O₃ glasses are formed on the surface of ceramic by B4C oxides. B₂O₃ is observed as the major phase in SiC matrix. With the temperature increasing, SiO₂ phases are formed, and combined with B₂O₃ phases to form the liquid borosilicate glass. When the temperature rises to 1200 ℃, the borosilicate glass will decomposes into SiO₂ and gaseous B₂O₃. At 1350 ℃, the content of B₂O₃ decreases rapidly for borosilicate glass decomposing into B₂O₃ which volatilizes itself. On the other hand, high temperature will cause the viscosity of borosilicate glass to decrease, hence, accelerates the oxygen diffusion. SiC/SiC–B₄C composites retain great mechanical properties at 1200 ℃ for 50 h. The main mechanisms are that borosilicate glass oxidized from B₄C can heal cracks in the composites effectively.