The present paper is concerned on the effect of infiltration temperature on the components, microstructure, and mechanical properties of reaction-bonded boron carbide (RBBC) ceramics. RBBC ceramics were fabricated by reactive infiltration of molten silicon (Si) into porous preforms containing boron carbide (B4C) and free carbon. It has been found that infiltration temperatures have significant influence on the infiltration reactions involved and therefore the evolution of different phases formed in the RBBC ceramics. An increase in grain size of boron carbide particles through the coalescence of neighboring grains was observed at certain infiltration temperatures. The morphology of silicon carbide (SiC) phases developed from discontinuous and cloud-like SiC to continuous and integrated SiC zones with the increase of infiltration temperatures. With increasing temperatures up to 1600 degrees C, the hardness, flexural strength, and fracture toughness all increased. When the temperatures exceeded 1600 degrees C, while the hardness and flexural strength decreased, the fracture toughness continued to increase.