The microstructure of the as-cast 2D70 aluminum alloy and its evolution during 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 results indicate that the microstructure of the as-cast 2D70 aluminum alloy mainly consists of the dendritic network of aluminum solid solution and intermetallic compounds (Al(2)CuMg, Al(2)Cu, Al(9)FeNi, Cu(2)FeAl(7), and Al(7)Cu(4)Ni). After conventional homogenization, Al/Al(2)CuMg eutectic phases are dissolved into the matrix, and a small amount of high melting-point eutectic Al/Al(2)Cu phases exist in the matrix, resulting in an increase in the starting melting temperature. Under double homogenization, the high melting point Al/Al(2)Cu phases are dissolved, and no obvious change is observed for the size and morphology of Al(9)FeNi, Cu(2)FeAl(7), and Al(7)Cu(4)Ni compounds.