Abstract: In this study, 7050-T7451 aluminum alloy plate was used as the research material, and M(T) specimens for crack growth were prepared. The crack growth stage in the fatigue crack growth rate test was carried out using the increasing-K method with different gradient values. The influence of different gradients on the crack growth stage in the fatigue crack growth rate test was recorded from the da/dN-ΔK curves.The results show that when the gradients during the crack growth stage were set at 0.04, 0.06, and 0.08 respectively, the data-fitted curves indicated that different gradients had no significant effect on the fatigue crack growth rate. However, the test data revealed that a larger gradient corresponded to a higher test force and shorter fatigue cycles. In practical applications, when the test force and stroke of the equipment were sufficient, a larger gradient could shorten the test duration and significantly improve the test efficiency.