By means of long-term aging treatment, creep properties measurement and microstructure observation, the influences of long-term aging on the microstructure and creep behaviors of FGH95 Superalloy are investigated. Results show that the fine γ′ particles dispersedly precipitate in the alloy after fully heat treated, and coarser γ′ phase discontinuously distribute along the grain boundaries. After the alloy is long-term aged at 723 K for 500 h, the fine γ′ phase with better cube degree and carbide particles distribute dispersedly in the alloy to enhance the creep resistance of the alloy for possessing a longer creep lifetime at the condition of 923 K and 1034 MPa. The deformed feature of the alloy is that configurations of slipping dislocations and the stacking fault appear in the alloy. As the creep goes on, the cracks initiate and propagate along the boundaries due to dislocations tangling in the grain boundaries for bringing out the stress concentration.