Erbium　is　an　effective　micro-alloying　element　in　aluminum　alloys　and　has　been　investigated　intensively.　Similar　with　the　addition　of　Sc　in　aluminum　alloys,　nano-sized　L12-ordered　Al3Er　precipitates　were　formed　coherently　with　the　matrix　in　Er-containing　micro-alloying　aluminum　alloys.　Further,　in　the　case　of　the　addition　of　both　Er　and　Zr,　core-shell-structured　Al3(ZrxEr1-x)　precipitates,　instead　of　Al3Er,　were　observed　in　a　fine　dispersion.　Those　thermally-stable　precipitates　can　refine　the　grain　size,　minimize　the　segregation,　homogenize　the　microstructure,　enhance　the　strength,　hinder　the　recrystallization,　and　thus　improve　the　comprehensive　performance　of　the　aluminum　alloys.　This　paper　presents　the　effect　of　Er　on　the　microstructure,　mechanical　properties　and　thermal　stability　of　aluminum　alloys.　The　research　of　some　typical　commercial　aluminum　alloys　containing　Er,　is　also　reviewed　here.　©　2017　Trans　Tech　Publications,　Switzerland.