Abstract: The solid solution and aging process for a second generation Ni-based single crystal superalloy was investigated by the assistance of thermodynamic calculation, DSC curve and metallography. Results show that cast γ/γ′ eutectic in the superalloy was dissolved after step-wise solid solution at 1 315 ℃ for 4 h. After followed aging at 1 150 ℃×4 h, the size of cuboidal γ′ was 0.44 μm and its volume fraction was 62%. After the solid solution, first level aging and then the second aging at 870 ℃ for 24 h, this alloy showed excellent rupture property as good as that of foreign similar materials.