The　effects　of　trace　addition　of　Al　on　the　microstructure　and　mechanical　properties　of　the　as-extruded　Mg-6Zn-0.5Er　alloy　were　investigated　in　the　present　investigation.　The　results　showed　that　the　trace　addition　of　Al　affected　the　mechanical　properties　significantly.　The　elongation　of　the　extruded　alloy　was　improved　markedly　from　17　to　25%　with　the　trace　addition　of　Al.　It　is　suggested　that　the　improvement　of　ductility　was　mainly　attributed　to　the　modification　of　basal　texture　of　the　as-extruded　alloy,　resulting　from　the　complete　dynamic　recrystallization　due　to　the　trace　addition　of　Al.　In　addition,　the　existence　of　the　complete　dynamic　recrystallization　led　to　an　obvious　increase　in　the　number　fraction　of　high　angle　grain　boundaries,　the　average　misorientation　angle　and　Schmid　factors　for　the　(0001)　＜　11　(2)　over　bar0　＞　slip,　which　also　have　contributed　to　the　improvement　of　ductility.　(C)　2016　Production　and　hosting　by　Elsevier　B.V.　on　behalf　of　Chongqing　University.