The in situ synthesized TiB reinforced titanium matrix composites have been prepared by spark plasma sintering at 800–1200 ℃ under 20 MPa for 5 min. The effects of sintering temperature and reinforcement volume fraction on flexural strength, Young’s modulus and fracture toughness of the composites are investigated. The titanium matrix consists of α-Ti and β-Ti phases, and the volume fraction of β-Ti increases with increasing sintering temperatures. The in situ synthesized TiB reinforcements are distributed randomly and uniformly in matrix. The transverse section of TiB has a hexagonal shape aligned along [010] direction, and the crystallographic planes of the TiB needles are always of the type (100); (101) and (101). The 10 vol% TiB reinforced composite sintered at 1000 ℃ exhibits excellent mechanical properties. The flexural strength, Young’s modulus and fracture toughness of this composite are 1560 MPa, 137 GPa and 8.64 MPa·1/2, respectively.