Abstract: The evolution behavior of microstructure and strengthening phase of GH710 alloy after hot extrusion and heat treatment, and the influence on alloy mechanical properties were studied. The results indicate that the microstructure of as-cast alloy is broken and recrystallized after hot extrusion, and the recrystallized microstructure is further refined and more uniform with the increase of extrusion ratio. There are three different types of γ’ phases in the extruded alloy. The primary γ’ phases are mostly distributed on the grain boundary and the intersection of three grains, with an average size of986.3 nm. The secondary γ’ phases are mainly distributed inside the grains, with an average size of 484.6 nm. The finer tertiary γ’ phases less than 100 nm are distributed among secondary γ’ channels. After the heat treatment, the primary γ’phase are completely dissolved, the grain size increases rapidly, and the volume fraction of secondary γ’ phase and tertiaryγ’ phase increase,which helps to improve the comprehensive properties of the alloy. When the extrusion ratio is increased to 4, the tensile strength and plasticity are significantly improved at room temperature, and the failure mechanism changes from brittle intergranular fracture to transgranular and intergranular mixed fracture.