Abstract: TB6 titanium alloy was fabricated via laser directed energy deposition (LDED), and the anisotropic characteristics of the microstructure and mechanical properties across different sample cross-sections were systematically investigated, the influence of heat treatment on Anisotropy in Microstructure and Mechanical Property were analized. Results indicate that the as-deposited specimen exhibited near-equiaxed grains in the cross-section vertical to the deposition direction, while a columnar/equiaxed grain composite structure was observed in the cross-section parallel to the deposition direction. Both cross-sections displayed a lamellar basketweave microstructure, with the α phase in the cross-section vertical to the deposition direction demonstrating a more elongated morphology. This distinct grain structure and α phase configuration endowed the transverse sample with superior microhardness (389.6 HV), tensile strength (1337 MPa), and reduced elongation (2.9%), exhibiting pronounced mechanical anisotropy compared to the longitudinal sample. Post heat treatment induced coarsening of the lamellar α phase with reduced width heterogeneity, resulting in a significant decrease in the elongation anisotropy index (IPA) from 99.1 (as-deposited) to 33.2. Fractographic analysis revealed a transition from shallow dimples to deep microvoid coalescence, effectively mitigating the mechanical anisotropy.