The B4C-ZrB2-SiC ternary composites with super hard and high toughness were obtained by arc melting in argon atmosphere. Microstructures were observed by SEM, and phase compositions were analyzed by XRD. The hardness and fracture toughness of ternary composites are 28？GPa and 4.5？MPa·m1/2. The eutectic mole composition is 0.39B4C-0.25ZrB2-0.36SiC, and the eutectic lamellar microstructure is composed of B4C matrix with the lamellar ZrB2 and SiC grains.
