The influence of stress on the microstructural stability of the DD10 single crystal superalloy was investigated using SEM after long-term aging at 1100°C and stress rupture testing at 1100°C/140 MPa. The results indicate that the TCP (topologically-close-packed) phases formed after aging at 1100°C for 253 h and stress-rupture at 1100°C/140 MPa are μ phases enriched with Re, W, Cr and Mo. The stress promotes the formation of μ phase, and the amount of μ phase increases with the stress increasing at 1100°C/140 MPa. However, stress does not influence the type and morphology of TCP phase. In addition, the stress accelerates the rafting process of γ'.