This　present　work　explored　the　welding　process　of　gas　metal　arc　welding　for　4mm　5E61　Er-containing　aluminum　alloy,　and　then　analyzed　the　microstructure　and　mechanical　properties　of　the　welded　joint.　The　results　demonstrated　that　when　the　welding　current　was　160A-220A,　the　welded　joint　penetration　depth　range　was　5.75mm　to　6.72mm,　the　melting　width　ranging　from　9.68mm　to　11.61mm.　When　the　arc　voltage　increased　from　17.5V　to　22.5V,　the　penetration　depth　of　the　welded　joint　reduced　from　6.95mm　to　5.57mm,　and　the　melting　width　ranged　from　6.64mm　to　11.86mm.　When　the　welding　current　was　170A,　the　arc　voltage　was　17.5V,　and　the　welding　speed　was　10mm/s.　In　the　third　case,　a　fully　penetrated　welded　joint　can　be　obtained　and　the　joint　strength　was　the　highest　value.　The　yield　strength　reached　192　MPa,　the　tensile　strength　can　be　301　MPa,　and　the　fracture　location　occurred　in　the　HAZ.　The　weld　zone　of　the　welded　joint　mainly　consist　of　the　equiaxed　dendrites　size　of　50　μm.　The　micro-hardness　of　the　weld　zone　was　lower　than　that　of　the　base　metal,　and　there　was　no　obvious　softening　phenomenon　in　the　heat　affected　zone.　©　2020　Trans　Tech　Publications　Ltd,　Switzerland.