In order to improve the oxidation resistance of the TaB2–SiC based coating applied on carbon/carbon (C/C) composites, TaC phase was in-situ introduced and a TaB2–TaC–SiC ultra-high temperature ceramics (UHTCs) coating was prepared on the surface of SiC coated C/C composites by in-situ synthesis method. The results showed that the outer coating consists of smooth non-angular TaB2 phase, regular hexagonal prism shape TaC phase and SiC phase, which are synchronously obtained during the preparation of the coating. The multilayer coating could protect the C/C composites against oxidation for 400h at 1773K in air with only 1.43% weight loss. A double self-healing oxidation layers (inner SiO2 glass layer and outer compound Ta–Si–O silicate glass layer) formed on the surface of the coating provides a dual oxidation protection for the coating, which was responsible for the excellent oxidation resistance.