The　effect　of　retrogression　and　re-aging　treatment　(RRA)　on　properties　and　microstructure　of　a　new　type　of　Al-Zn-Mg-Er-Zr　alloy　are　investigated.　The　results　show　that　extending　retrogression　time　is　beneficial　to　improve　intergranular　corrosion　(IGC)　and　exfoliation　corrosion　(EXCO)　resistance　but　decreases　the　strength.　The　mechanical　properties　and　corrosion　resistance　of　the　studied　alloy　are　associated　with　the　grain　interior　precipitates,　grain　boundary　precipitates　(GBPs)　and　precipitates　free　zone　(PFZ).　Fine　eta;　phases　of　the　grain　interior　gradually　dissolve　in　the　matrix,　and　the　residual　g;　phases　transform　to　eta　phases　during　retrogression　treatment.　Re-precipitation　of　the　dissolved　g;　phases　will　result　in　a　denser　and　finer　g;　phases　in　the　grain　interior　after　re-aging　treatment.　The　GBPs　are　more　coarse　and　discrete　distribution,　and　the　PFZ　becomes　wider　as　the　retrogression　time　increases.　And　the　effect　of　Al-3(Er,Zr)　precipitates　on　the　comprehensive　performance　of　the　studied　alloy　has　also　been　discussed　in　detail.