ZrB 2–SiC/ZrSi 2 ceramics containing 30 vol% carbon fiber (C f) additive were fabricated by hot pressing at low temperature (1500 ℃) using submicron ZrB 2 powders, and their microstructural evolution and performance were investigated. The addition of SiC or ZrSi 2 significantly reduced the onset sintering temperature and enhanced the densification of ZrB 2. ZrB 2–ZrSi 2–C f showed poor performance owing to the serious fiber degradation, while the fiber degradation was effectively inhibited in ZrB 2–SiC–C f resulting in high fracture toughness, substantial fiber pull-out, and non-brittle fracture mode for such material. The critical thermal shock temperature difference of ZrB 2–SiC–C f was up to 741 ℃, significantly higher than those of ZrB 2–SiC/ZrSi 2 and ZrB 2–ZrSi 2–C f. Moreover, this composite displayed a good oxidation resistance at 1500 ℃ in air.