The Ni-based superalloy GTD-111DS has been widely used as the material of the first stage blade of gas turbine. But there are little data available on the microstructure and mechanical property. The strength and ductility of GTD-111DS decrease more rapidly due to the acceleration of its microstructure degradation under high temperature. The results of study showed that the shape of γ' did not change with increased aging time but the amount and volume fraction of the deposition of secondary γ' increased and secondary γ' grew among primary γ'. Also there was difference of yield strength and tensile strength in room temperature according to heat treatment and collecting region.