The effects of solid solution temperature and aging time on the microstructure and mechanical properties of Inconel 617 superalloy are studied by using optical microscope， scanning electron microscope， and transmission electron microscope. The results show that the main precipitated phase in the solid solution microstructure of Inconel 617 superalloy is M ₂₃C₆ type carbide， and the nucleation growth is preferentially at the grain boundary. With the increase of solid solution temperature， the grain boundaries and intragranular carbides undergo two processes： first growing and then dissolving， and the average growth rate of the grain size also increases. As the aging time prolongs， the γ′ phase precipitates dispersedly and distributes uniformly in the microstructure，showing a trend of grain quantity decrease and grain size increase. As the size of the γ′ phase increases， its lattice mismatch also increases， and the elastic strain field around the γ′ phase is enhanced， resulting in a more obvious strengthening effect. High- temperature tensile properties testing shows that the tensile strength and yield strength of Inconel 617 alloy gradually decrease at 750 ℃ with the increase of solid solution temperature， while they gradually increase at 900 ℃. The grain boundary strength of Inconel 617 alloy is higher than the inner grain strength at ≤750 ℃， while the inner grain strength is higher than the grain boundary strength at 900 ℃. The tensile strength and yield strength of Inconel 617 alloy at 750 ℃ increase gradually with the aging time.