The influence of aging temperature on the microstructure and mechanical properties of TB6 titanium alloy fabricated via selective laser melting (SLM) was investigated. The results indicate that the microstructure of SLM-deposited TB6 alloy primarily consists of columnar β phase and equiaxed α phase, with lamellar or granular αp phase and grain boundary αGB phase precipitating after solution aging. As the aging temperature increases, the size of the α phase gradually decreases, the volume fraction of lamellar α phase diminishes, and the content of granular αP phase increases. Tensile property tests reveal that the tensile strength of the material decreases while plasticity increases with rising aging temperature. Specifically, the tensile strength of samples aged at 560 ℃ decreased to 1129 MPa compared to 1386 MPa for those aged at 520 ℃, whereas elongation increased from 7.1% to 10.3%. It is concluded that changes in the morphology and size of the α phase significantly impact the strength and plasticity of the alloy. Reducing the volume fraction of lamellar αL phase and increasing the volume fraction of granular αP phase contribute to achieving better strong-plasticity matching. Elevating the aging temperature can decrease the volume fraction of lamellar αL phase and enhance the plasticity of the material.