B4C ceramics were obtained using hot-pressing method. The effect of different sintering temperatures on the microstructures and mechanical properties of B4C ceramics were investigated. Oxidation resistances were studied over the range 600-850°C. The experimental results showed that the relative density, bending strength and fracture toughness all increased first and then decreased with increasing the sintering temperature. The Vickers-hardness increased as the sintering temperature increasing. When the sintering temperature was 1950°C, the B4C ceramics showed the optimized properties. The values of its relative density, Vickers-hardness, bending strength and fracture toughness were 99.1%, 34.0 GPa, 524.6 MPa and 6.56 MPa·m1/2, respectively.