The　effect　of　homogenization　treatment　on　aging　behavior　of　Al3(Sc,　Zr)　and　homogeneity　of　Mg　were　studied　in　Al-6Mg-0.4Mn-0.15Zr-0.04Sc　alloy　using　Micro-hardness　test,　optical　microscope,　scanning　electron　microscope　and　transmission　electron　microscope.　The　peak　hardness　HV　of　the　alloy　annealed　at　the　normal　homogeneous　temperature　of　475℃　was　830　MPa,　much　lower　than　920℃　of　that　isochronally　annealed　at　175~550℃,　demonstrating　that　the　alloy　does　not　obtain　the　sufficient　aging　strengthening　from　Al3(Sc,　Zr)　particle　during　one-stage　annealing　at　475℃.　Therefore,　two-stage　homogeneous　treatment　was　designed.　The　first　stage　annealing　was　between　275~350℃,　where　at　300℃　exhibits　the　highest　peak　hardness　of　870　MPa,　and　the　second-stage　annealing　was　performed　at　475℃　with　the　peak　hardness　of　920　MPa.　The　microstructure　analyses　indicate　the　Al3(Sc,　Zr)　particles　in　the　two-stage　annealing　are　much　finer　than　those　of　one　step　annealing.　After　annealing　at　300℃/7　h+　475℃/15　h,　the　segregation　of　Mg　disappears　and　the　Al3(Sc,　Zr)　particles　form　dispersedly　at　the　same　time.　Finally,　a　higher　strength　and　a　higher　recrystallization　temperature　are　obtained.　©　2020,　Science　Press.　All　right　reserved.