Variable　polarity　plasma　arc　welding　(VPPAW)　was　used　to　weld　5E61　aluminum　alloy　plates　with　4　mm　in　thickness.　The　results　showed　that　high　quality　welded　joints　could　be　obtained　under　the　specified　conditions　and　welding　parameters.　Whether　the　5E61　aluminum　alloy　filled　with　ER5356　or　5E61　filler　wire,　the　microstructures　in　the　weld　were　fine　and　homogeneous,　but　the　microstructures　in　the　fusion　zone　were　slightly　coarsened　compared　with　the　microstructure　in　the　weld.　When　the　ER5356　wire　was　used　as　filler　wire,　metal　phases　were　dissolved　fully　in　the　weld　zone,　and　the　welded　joint　strength　was　reduced.　If　5E61　filler　wire　was　used,　a　portion　of　Er　element　was　precipitated　as　the　second　phase,　the　size　of　the　phase　unit　was　very　close　to　Al　matrix　with　a　small　misfit　degree,　so　the　mechanical　properties　of　welded　joints　were　improved.　The　results　show　that　the　hardness　of　welded　joints　could　reach　up　to　85%　of　that　of　the　5E61　aluminum　alloy　base　metal.　©　2018,　Editorial　Board　of　Transactions　of　the　China　Welding　Institution,　Magazine　Agency　Welding.　All　right　reserved.