Microstructural evolutions and mechanical properties of Al–Mg–Mn–Zr–Ti–Er alloy after homogenization were investigated in detail by optical microscope (OM), scanning electronic microscope (SEM), transmission electronic microscope (TEM), energy dispersive spectrum (EDS) and tensile test. A maximum tensile strength is obtained when the alloy homogenized at 510°C for 16h. With increasing preheating temperature (200–400°C), the strength of the alloy finial homogenized at 490°C for 16h increases. When the preheating temperature is ≥300°C, the strengths of the two-step homogenized alloys are higher than those of the single homogenized alloys. The preheating stage plays an important role in the microstructures and properties of the final homogenized alloy. Many fine (Mn,Fe)Al 6 precipitates when the preheating temperature is 400°C. ErAl 3 phase cannot be observed during preheating stage. Plenty of fine (Mn,Fe)Al 6 and ErAl 3 precipitate in finial homogenized alloy when the preheating temperature is ≥300°C. The Al–Mg–Mn–Zr–Ti–Er alloy is effectively strengthened by substructure and dispersoids of (Mn,Fe)Al 6 and ErAl 3 .