Abstract: This study investigated the influence of graded Zn content on the evolution of precipitated and iron-rich phases and grain structure of the alloys, designed and developed the Al–8.0Zn–1.5Mg–1.5Cu–0.2Fe (wt%) alloy with high strength and formability. With the increase of Zn content, forming the coupling distribution of multiscale precipitates and iron-rich phases with a reasonable matching ratio and dispersion distribution characteristics is easy. This phenomenon induces the formation of cell-like structures with alternate distribution of coarse and fine grains, and the average plasticity–strain ratio (characterizing the formability) of the pre-aged alloy with a high strength is up to 0.708. Results reveal the evolution and influence mechanisms of multiscale second-phase particles and the corresponding high formability mechanism of the alloys. The developed coupling control process exhibits considerable potential, revealing remarkable improvements in the room temperature formability of high-strength Al–Zn–Mg–Cu alloys.