Effect　of　Er　on　microstructure　and　mechanical　properties　of　Al-Zn-Mg　alloy　as　well　as　the　wear　behavior　of　the　alloy　under　different　loads　were　studied　by　means　of　scanning　electron　microscopy　(SEM),　energy　dispersive　spectrometer　(EDS),　transmission　electron　microscopy　(TEM)　and　material　surface　comprehensive　tester.　The　results　show　that　with　the　addition　of　Er,　the　elongation　of　the　alloy　is　increased　by　about　30%　and　the　grain　size　is　significantly　refined　as　the　average　grain　size　reduces　by　about　68%.　The　alloy　experiences　two　stages　of　running-in　and　stable　wear　during　wear　process,　and　the　wear　factor　curves　fluctuate　with　the　increasing　of　load.　The　enrichment　of　O　element　in　the　tribolayer　indicates　the　oxidation　wear　mechanism.　Under　the　load　of　30　N,　the　wear　mechanism　is　mixed　up　by　the　abrasive　wear,　fatigue　wear　and　adhesive　wear.　Under　the　load　of　70　N,　the　wear　mechanism　was　mainly　the　abrasive　wear　with　fatigue　wear,　and　the　wear　loss　is　reduced　due　to　the　decrease　of　surface　delamination　of　the　alloy　with　the　addition　of　Er.　©　2023　Chinese　Mechanical　Engineering　Society　of　Heat　Treatment.　All　rights　reserved.