In this work, the microstructure evolution and mechanical properties of the heat treated Ti-48Al-2Cr-2Nb alloy prepared by selective electron beam melting (SEBM) were investigated. The results indicate that as the heat-treatment temperature increases, the fine duplex microstructure and equiaxed γ bands of Ti-48Al-2Cr-2Nb alloy gradually coarsen and transform into lamellar structure. When the heat treatment processes are 1290 ℃×4 h, 1315 ℃×1.5 h, and 1335 ℃×0.5 h, the main microstructures of the alloy are duplex structure, near-lamellar structure, and fully lamellar structure, respectively. Compared with the as-deposited sample, the average widths of equiaxed γ bands under these heat treatments increase from 28.5μm to 115.5 μm, 291.4 μm and 332.5 μm, respectively. Meanwhile, the average tensile strength of the longitudinal specimens decreases from 698 MPa to 541 MPa, 461 MPa and 390 MPa, respectively, with no obvious change in elongation. In addition, the mechanical properties of all the transverse specimens are better than the longitudinal specimens after heat treatments. This is because the weakened interface strength between the coarsened equiaxed γ bands and the duplex microstructures easily leads to the generation of microcracks under tensile stress, resulting in a decrease in the tensile strength of longitudinal specimens. During heat treatment, the heterogeneity of mechanical properties of the alloy increases gradually. The tensile strength difference between transverse and longitudinal specimens gradually increases, reaching a maximum of 102 MPa at 1335 ℃×0.5 h. These results provide theoretical guidance and data support for the selection of heat treatment for Ti-48Al-2Cr-2Nb alloy blades manufactured by SEBM.