Samples　of　Al-Mg-Mn　and　Al-Mg-Mn-Er-Zr　alloys　were　welded　using　the　method　of　laser　welding.　The　influence　of　Er　and　Zr　on　microstructure,　microhardness　and　mechanical　properties　of　the　Al-Mg-Mn　alloy　welded　joints　were　investigated.　It　has　been　found　that　addition　of　Er　and　Zr　refines　the　grain　size　in　the　fusion　zone,　due　to　the　formation　of　primary　Al3Zr　and　Al3Er.　Fine　equiaxed　grains　are　dominated　near　the　fusion　boundary　of　the　Al-Mg-Mn-Er-Zr　alloy　joint,　which　is　contrary　with　the　columnar　crystal　in　the　Al-Mg-Mn　alloy　joint.　Microhardness　of　the　center　of　the　fusion　zone　rises　from　74HV(0.1)　to　84HV(0.1)　owing　to　the　grain　refinement　by　Er　and　Zr.　The　tensile　test　result　shows　that　the　ultimate　tensile　strength　and　yield　strength　are　improved　by　adding　Er　and　Zr.　The　main　reason　for　this　is　related　to　grain　refining　strengthening.　(C)　2012　Elsevier　B.V.　All　rights　reserved.