The　microstructure　evolution　of　Al-Zn-Mg-Cu　alloy　with　erbium　was　studied　by　optical　microscope　(OM),　scanning　electron　microscope　(SEM),　transmission　electron　microscope　(TEM)　during　homogenization　process.　The　results　showed　that　there　were　serious　component　segregation　in　the　as-cast　structure　of　the　alloy,　mainly　composed　of　T(AlZnMgCu),　S(Al2CuMg)　and　a　small　amount　of　Al8Cu4Er　and　Al7Cu2Fe.　The　overheating　temperature　of　the　alloy　was　482.5　℃.　After　homogenized　at　470　℃　for　24　h,　the　dissolution　of　T(AlZnMgCu)　phase　and　S(Al2CuMg)　phase　reached　to　a　balance,　but　the　residual　Al8Cu4Er　phase　could　not　be　dissolved　completely.　Compared　with　single-stage　homogenization,　Al3(Er,Zr)　dispersion　phase　with　smaller　grain　size　and　more　uniform　distribution　can　be　obtained　after　two　stage　homogenization　process　of　400　℃　for　8　h　followed　by　470　℃　for　24　h.　By　comparing　the　residue　of　non-equilibrium　eutectic　phase,　two-stage　homogenization　is　the　best.　©　2021　Trans　Tech　Publications　Ltd,　Switzerland.