<p>The relationship between tensile and fatigue properties in Al alloys remains vague because strengthening often affects the fatigue damage in many aspects. In this study, 7xxx Al alloys were strengthened solely by varying the precipitate content while keeping both the overall microstructure and damage mechanisms consistent, so as to examine the intrinsic effect of strengthening on its fatigue performance. The results show that there was an increment of 100 MPa in tensile strength, while the fatigue strength remained nearly unchanged. Further analysis indicates that the strengthening had a dual-edged effect, that is, strengthening enhanced the whole resistance to plastic deformation, while also causing the strain localization. Combining our previous models associated with the tensile and fatigue properties, a relationship between yield and fatigue strengths is established, which shows a first increasing and then declining trend in the fatigue strength with increasing the yield strength, leaving a relatively stable region in between, which explains the plateau phenomenon of fatigue strength in a middle yield strength range for the high-strength 7xxx alloys.</p>