Magnesium　alloys　have　attracted　significant　attention　due　to　their　excellent　characteristics,　such　as　low　density,　high　specific　strength,　high　thermal　conductivity,　and　superior　damping　ability.　The　prominent　advantages　of　using　magnesium-alloy　parts　are　environmental　protection,　energy　conservation,　and　emission　reduction,　especially　forged　magnesium-alloy　parts,　which　are　used　to　reduce　the　weight　of　equipment　in　transportation　and　aerospace　fields.　Presently,　there　are　relatively　few　investigations　on　the　forged　Mg-RE　alloys.　Based　on　Mg-Gd　binary　alloy,　a　series　of　Mg-Gd-Er-Zr　alloys　were　developed,　exhibiting　excellent　room-temperature　mechanical　properties　and　high-temperature　creep　resistance.　In　this　study,　the　Mg-8Gd-1Er-0.5Zr　(mass　fraction,　%)　alloy　was　conducted　using　a　multidirectional　forging　(MDF)　at　a　high　strain　rate.　The　microstructure　and　texture　evolution　in　various　accumulated　strains　(Sigma　Delta　epsilon)　were　examined,　and　their　effects　on　the　mechanical　properties　of　the　alloy　were　discussed.　The　results　showed　that　the　{10　(1)　over　bar2}　extension　twinning　was　activated　within　most　grains　in　the　early　stage　of　forging.　With　an　increase　in　Sigma　Delta　epsilon,　the　area　fraction　of　twin　decreases,　while　the　area　fraction　of　recrystallization　increases.　Continuous　dynamic　recrystallization　(CDRX)　was　the　dominant　mechanism,　supplemented　by　discontinuous　dynamic　recrystallization　(DDRX)　and　twin-induced　recrystallization　(TDRX).　The　grain　refinement　was　attributed　to　the　twin-breaking,　and　the　grain　size　decreased　from　33.0　mm　to　13.1　mu　m　when　Sigma　Delta　epsilon　was　less　than　1.32.　However,　it　was　attributed　to　the　dynamic　recrystallization,　and　the　grain　size　was　further　refined　to　4.2　mu　m　when　Sigma　Delta　epsilon　was　greater　than　1.32.　As　Sigma　Delta　epsilon　increases,　the　texture　of　the　alloy　changed　from　basal　to　double-peak　texture,　and　its　intensity　increased.　When　Sigma　Delta　epsilon　=　0.66,　the　tensile　strength,　yield　strength,　and　elongation　at　room-temperature　of　the　MDFed-alloy　reached　295　MPa,　252　MPa,　and　13.8%,　respectively,　which　were　80%,　157%,　and　13.1%　higher　than　those　of　the　assolution　state.