ZrC–SiC coating on Cf/ZrC–SiC composite was fabricated via in situ reaction using zirconium powder, silicon powder, and phenolic resin as raw materials. The coated composites exhibited excellent oxidation performance. In particular, the coating closely adhered onto the composites, and had a uniform thickness of approximately 90 μm and did not show significant cracking. Even after 30 min of oxidation at 1700 °C in a muffle furnace, the coating thickness of 90 μm remained. Meanwhile, the density of the coating was increased with oxidation because the pores on the surface were filled with the mixtures of ZrC, ZrO2, and SiC. Three distinct layers were formed in the composite, namely, surface oxide, intermediate and unoxidised layers. Therefore, the coating effectively protected the composites from oxidation.