The increasing demand for light-weight and high-performance materials for the aerospace industry in recent years has led to the development of metal matrix composites (MMCs). As typical MMCs, titanium matrix composites (TMCs) have been regarded as potential candidates due to their high specific strength, outstanding wear resistance as well as excellent mechanical properties at high temperatures. However, it is difficult to achieve a superior titanium matrix composites with high strength and high plasticity simultaneously. In this study, the in-situ reinforced titanium matrix composites were fabricated using low-oxygen HDH Ti powders and polycarbosilane (PCS) via a powder metallurgy method, including solution-assisted wet mixing and pressureless sintering. The effects of PCS addition on the oxygen inhibition, sintering densification, microstructure and mechanical properties of the composites were investigated. Results show that the solution-assisted wet mixing process makes the Ti powders coated with PCS, which can effectively control the oxygen contamination. The oxygen content of the fabricated Ti-1.0 wt.% PCS composite is 0.21~0.24 wt.%, much lower than that of 0.36~0.41 wt.% for CP-Ti. During sintering, the pyrolysis products of PCS can react with Ti matrix to in-situ synthesized TiC particles, while Si element is dissolved in matrix. The incorporation of PCS can improve the mechanical properties of the Ti matrix. The Ti-1.0 wt.% PCS composite sintered at 1200 °C for 2 h possesses the best mechanical properties, with a relative density of 98.4%, a Rockwell hardness of 47.3 HRC, a yield strength of 544 MPa, a ultimate tensile strength of 650 MPa, and a elongation of 14.5%, which is obviously higher than CP-Ti.