Abstract: Fatigue tests were carried out on B95 and 7B04 superhard aluminum alloys under the random load spectrum compiled by the flight characteristics of a domestic aircraft, and the fatigue crack growth data and total fatigue life were obtained. The crack formation life was determined, and the fatigue life, dispersion coefficient and other important fatigue property indexes of the two aluminum alloys were compared and analyzed. The results show that the median crack formation life of 7B04 aluminum alloy was 5 301.9 flight hours, which was about 1.55 times that of B95 aluminum alloy, and the dispersion coefficient of crack formation life was 1.436 2, which was far lower than that of B95 aluminum alloy (2.443 9). The safe life of 7B04 aluminum alloy was 4 373.82 flight hours, which was about 2.2 times that of B95 aluminum alloy, and the total life dispersion coefficient was 1.502 3, which was far lower than that of B95 aluminum alloy (2.168 9). The fatigue crack growth properties of 7B04 aluminum alloy were obviously better than those of B95 aluminum alloy, so it could be used to replace B95 aluminum alloy to manufacture structural members.