Abstract: A new single crystal superalloy was aged at high temperature (1 100 ℃), and the effect of different aging times (0, 200, 400, 600, 800, 1 000 h) on the microstructure and high temperature (1 100 ℃) tensile properties of the superalloy was investigated. The results show that the microstructure of the new single crystal superalloy before and after aging was composed of γ matrix phase and γ' phase. The space of γ matrix channel and the size of γ' phase increased with increasing aging time. The needle shaped TCP phase with obvious orientation to matrix was precipitated in the alloy after aging for 600 h, and the volume fraction increased with the increase of aging time. With the aging time increasing, the yield strength and tensile strength of the single crystal superalloy at high temperature decreased, while the elongation and reduction of area after fracture increased first and then decreased. The tensile fracture surface of the single crystal superalloy all had features of necking and dimples before and after aging, and the fracture mechanism was dimple fracture.