Abstract: Objective This paper aims to reveal microstructure formation mechanism of TC4 remanufactured by laser powder bed fusion (LPBF) and its influence mechanism on performance. Methods LPBF forming was carried out on the forged TC4 matrix. Microstructure morphology of the matrix and deposited zone was characterized by metallographic microscope and scanning electron microscope, and tensile properties and fracture morphology at room temperature and high temperature were analyzed. Results LPBF deposited zone formed columnar grains with distinct directional solidification characteristics, and a large number of α′ phases were generated within the grains, which contributed to high strength but poor elongation after fracture. As a result, tensile strengths of the deposited alloy at room temperature and high temperature both exceeded 1 000 MPa, while elongation after fracture were relatively low, at 0.5% and 2.5%, respectively. Tensile fracture showed no obvious necking and exhibited typical brittle fracture characteristics. A good metallurgical bond was formed between the forged matrix and deposited alloy in the remanufactured TC4 titanium alloy. The tensile strength and elongation after fracture at room temperature and high temperature fell between those of the forged matrix and deposited alloy. Deformation and fracture failure of samples primarily occurred in the lower-strength forged matrix zone. Conclusion LPBF remanufactured TC4 has good forming quality and no defects. Interface bonding strength is higher than that of the forged matrix, and it can achieve high-precision remanufacturing and repair of complex components.