The laser-cladding-deposited TC4 titanium alloy is considerably anisotropic, and its mechanical properties are lower than the forging standards. In this study, boron (B) with different mass fractions is uniformly mixed into the TC4 powder by mechanical stirring, refining the microstructure and improving the comprehensive mechanical properties of the alloy. Results show that at a B mass fraction of 0.050%, the mechanical properties of the deposited TC4 titanium alloy exceed the forging standard, and the yield and tensile strengths become 1049 MPa and 1136 MPa, respectively. Furthermore, the elongation and area reduction become 11.50% and 33.5%, respectively, though the plastic anisotropy is larger than 30%. After solid solution and aging heat treatment with 950 ℃×1 h/air cooling +500 ℃×4 h/air cooling, the comprehensive mechanical properties are further optimized and the anisotropy is reduced to less than 5%. While we ensure suitable mechanical strength, the elongation and area reduction are enhanced to 16.70% and 37.3%, respectively.