Laser　beam　welding　of　aluminum　alloys　is　expected　to　offer　good　mechanical　properties　of　welded　joints.　In　this　experimental　work　reported,　CO2　laser　beam　autogenous　welding　and　wire　feed　welding　are　conducted　on　4　mm　thick　5083-H321　aluminum　alloy　sheets　at　different　welding　variables.　The　mechanical　properties　and　microstructure　characteristics　of　the　welds　are　evaluated　through　tensile　tests,　micro-hardness　tests,　optical　microscopy　and　scanning　electron　microscopy　(SEM).　Experimental　results　indicate　that　both　the　tensile　strength　and　hardness　of　laser　beam　welds　are　affected　by　the　constitution　of　filler　material,　except　the　yield　strength.　The　soften　region　of　laser　beam　welds　is　not　in　the　heat-affected　zone　(HAZ).　The　tensile　fracture　of　laser　beam　welded　specimens　takes　place　in　the　weld　zone　and　close　to　the　weld　boundary　because　of　different　filler　materials.　Some　pores　are　found　on　the　fracture　face,　including　hydrogen　porosities　and　blow　holes,　but　these　pores　have　no　influence　on　the　tensile　strength　of　laser　beam　welds.　Tensile　strength　values　of　laser　beam　welds　with　filler　wire　are　up　to　345.57　MPa,　93%　of　base　material　values,　and　yield　strengths　of　laser　beam　welds　are　equivalent　to　those　of　base　metal　(264.50　MPa).