Abstract: In-situ synthesized (TiB+La2O3)/TC4 composites with different reinforcements contents were produced by vacuum consumable arc melting and heat treatment utilizing the reactions between Ti,B and La,and the microstructure and mechanical properties of the composite were studied.The results show that the basketweave structure and dispersed reinforcements were obtained in the composites,the short fibrous TiB reinforcement distributed along processing direction and the La2O3 reinforcement was in short-rob like and granulated state.Compared with TC4 alloy,the room temperature tensile strength of the composites increased with the increase of TiB and La2O3 reinforcement contents and the renforcements had good potentiation to the substrate.The fracture mechanism of the composites was ductile rupture.