In this study, the as-cast microstructure of a high Zn-containing Al-Zn-Mg-CuZr alloy and its evolution during two-stage homogenization were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) analysis. The analysis shows the eutectic structures in as-cast the alloy were identified as α(Al) / Mg(Zn,Cu,Al) 2 , and also some Al 2 CuMg, Al 2 Cu and Fe-rich phases formed in the eutectic structures during solidification. With the prolonging of the second stage homogenization time, S(Al 2 CuMg), θ(Al 2 Cu) and Mg(Zn,Cu,Al) 2 phases orderly dissolved into the matrix, and the insoluble Fe-rich phases exist in all five as-homogenized schemes in this study, but Zn and Mg elements changes detected in the these particles during the two stage homogenization.