The study investigated the impact of heat treatment on the microstructure and tensile properties of GH4061 alloys fabricated by selective laser melting. Findings demonstrated that the as-built columnar grains experienced epitaxial growth spanning multiple molten pools, resulting in the formation of cellular substructures. Following heat treatment, as the solid solution temperature increased, there was a gradual shift in grain orientation towards the (101) and (111) crystal planes. The Laves phase transitioned from elongated chains to granular forms and dissolved at approximately 1060 ℃. The δ phases that precipitated at grain boundaries transformed from coarse bulk structures to disc-shaped, and eventually to short rod-shaped configurations. The average sizes of γ′ and γ″ phases are 23.53 nm, 24.43 nm, 25.34 nm and 25.66 nm at solution temperature of 980 ℃, 1020 ℃, 1060 ℃, 1100 ℃, respectively. The mechanical properties of the alloys after heat treatment show significant improvement at both room temperature and 650 ℃. Specifically, the tensile strengths at room temperature and 650 ℃ for the sample subjected to the 980 ℃ solid solution aging heat treatment are 1342 MPa and 1120 MPa, respectively. As the solid solution temperature increases, the room temperature tensile strength at 1020 ℃, 1060 ℃ and 1100 ℃ decreases by approximately 6.4%, 8.3%, and 10% than that at 980 ℃, respectively. At 650 ℃, the tensile strength at 1020 ℃, 1060 ℃ and 1100 ℃ decreases by approximately 7.9%, 8.8%, and 11% than that at 980 ℃, respectively, while the plasticity increases.