Abstract: The composites (TiB+La2O3)/Ti (TMCs) with different oxygen contents were synthesized by in-situ reaction between Ti and LaB6 using vacuum consumable electrode arc furnace melting technique; the phases, reinforcements morphology and microstructure of composites were analyzed; the tensile properties at room and high temperatures, as well as the thermal stability of the composites were also tested. The results show that the TMCs with higher oxygen contents had lower strength and plasticity at room temperature, while the composite had higher tensile strength at high temperatures, especially at 700 ℃; oxygen contents had little effect on strength after heat at 650 ℃ for 100 h, but the ductility of the composite with high oxygen contents was lower.