Mechanical　properties,　corrosion　resistance,　and　microstructure　of　Al　alloys　with　trace　element　erbium　were　studied.　Systemic　studies　in　the　pure　aluminum　and　5xxx　series　Al　alloys　showed　that　the　tensile　strength　was　significantly　improved　by　above　20%　with　little　loss　of　elongation　by　Er　alloying.　The　5xxx　series　Al　alloys　with　erbium　also　exhibited　excellent　corrosion　resistance.　Erbium　improved　the　aging　hardness　response　of　7xxx　series　Al　alloys　and　the　addition　of　0.4%Er　to　Al-Zn-Mg　alloys　increases　the　hardness　by　35MPa.　In　all　experiment　Al　alloys,　a　small　addition　of　0.1wt%　Er　induced　a　quick　increase　of　the　tensile　strength　and　the　amount　of　0.4%Er　shows　optimized　balance　of　the　strength　and　ductility.　The　Er　addition　improved　the　thermal　stability,　with　increasing　the　starting　Rex　temperature　about　50　degrees　C　in　all　investigated　Al　alloys.　With　regard　to　the　microstructure　mechanisms,　in　all　experimental　Al　alloys　Er　addition　has　significantly　refined　the　microstructure,　which　mainly　attributed　to　presence　the　Al3Er　particles.　In　the　7xxx　series　Al　alloys,　no　observable　PFZ　after　addition　of　0.4%　Er　was　found.　The　fatigue　property,　the　fracture　toughness　and　the　thermal　stability　of　microstructure　and　properties　are　on　the　way.