In　this　investigation,　a　high-strength　Mg-12Gd-1.0Er-0.5Zr　(wt.%)　alloy　sheet　was　produced　by　hot　extrusion　(HE)　and　subsequent　hard-plate　rolling　(HPR)　at　different　temperatures.　The　results　indicate　that　the　microstructures　of　these　final-rolled　sheets　are　inhomogeneous,　mainly　including　coarse　deformed　grains　and　dynamic　recrystallized　(DRXed)　grains,　and　the　volume　fraction　of　these　coarse　deformed　grains　increases　as　the　rolling　temperature　increases.　Thus,　more　DRXed　grains　can　be　found　in　R-385　°C　sheet,　resulting　in　a　smaller　average　grain　size　and　weaker　basal　texture,　while　the　biggest　grains　and　the　highest　strong　basal　texture　are　present　in　R-450　°C　sheet.　Amounts　of　dynamic　precipitation　of　β　phases　which　are　mainly　determined　by　the　rolling　temperature　are　present　in　these　sheets,　and　its　precipitation　can　consume　the　content　of　Gd　solutes　in　the　matrix.　As　a　result,　the　lowest　number　density　of　β　phase　in　R-450　°C　sheet　is　beneficial　to　modify　the　age　hardening　response.　Thus,　the　R-450　°C　sheet　displays　the　best　age　hardening　response　because　of　a　severe　traditional　precipitation　of　β＇　(more)　and　βΗ　/βΜ　(less)　precipitates,　resulting　in　a　sharp　improvement　in　strength,　i.e.　ultimate　tensile　strength　(UTS)　of　∼　518　±　17　MPa　and　yield　strength　(YS)　of　∼　438±18　MPa.　However,　the　elongation　(EL)　of　this　sheet　reduces　greatly,　and　its　value　is　∼　2.7　±　0.3%.　By　contrasting,　the　EL　of　the　peak-aging　R-385　°C　sheet　keeps　better,　changing　from　∼　4.9　±　1.2%　to　∼　4.8　±　1.4%　due　to　a　novel　dislocation-induced　chain-like　precipitate　which　is　helpful　to　keep　good　balance　between　strength　and　ductility.　©　2022