In this paper, Ti-6Al-4V matrix composites reinforced with 5% or 10% TiB and TiC were in situ synthesized by common casting and hot-forging technology utilizing the reaction between titanium and B4C. The phase constituents were identified by XRD while transus temperatures were determined by DSC and metallography. The evolution of microstructures was studied by optical microscopy. The effects of reinforcements on the microstructures, tensile properties and fractures at room temperature were discussed. The results show that yield strength and ultimate tensile strength increased significantly while ductility decreased with reinforcements increasing. Fracture type turned to brittle when reinforcements increased.