The creep-aging behaviors of 7075 aluminum alloy are studied by uniaxial tensile creep experiments under elevated temperatures. The effects of creep-aging temperature and applied stress on the precipitates of 7075-T651 aluminum alloy are investigated using scanning electron microscope (SEM) and transmission electron microscope (TEM). Results show that: (1) Coarse insoluble precipitates ( and ) and intermediate precipitates ( and ) are found in the aluminum matrix, and the effects of creep-aging treatment on these precipitates are not obvious; (2) The main aging precipitates are and phases, and the aging precipitates grow up with the increase of creep-aging temperature and applied stress; (3) With the increase of creep-aging temperature and applied stress, the precipitates are discontinuously distributed on the grain boundary, and the width of precipitate free zone increases with the increase of creep-aging temperature and applied stress; (4) Compared with the microstructure in the traditional stress-free aged sample, the creep-aging process can refine the precipitates and narrow the width of the precipitate free zone.