To achieve the long-term oxidation protection of carbon/carbon composites at low and medium temperatures, a SiC/B 4 C–B 2 O 3 –SiO 2 –Al 2 O 3 coating was applied on the composites. The coating exhibits a dual-layer structure with a dense SiC inner layer and B 4 C–B 2 O 3 –SiO 2 –Al 2 O 3 multi-phase outer layer. The effects of Al 2 O 3 contents and oxidation temperatures on the oxidation behavior of the coated C/C were investigated. The results shows that the coating with 7.7wt.% Al 2 O 3 performs excellent self-healing ability and can protect the C/C composites with weight losses of less than 1% for 250h at 800°C and for 90h at 900°C and 1000°C.