10mm-5A06 aluminum alloy was butt-welded in a single pass by the plasma-gas metal arc (plasma-MIG) welding procedure, the joints were subjected to X-ray inspection, the microstructure and mechanical performance of weld were also studied. The results indicate that plasma-MIG welding is superior to regular conventional MIG welding on the aspects of reducing weld porosity, increasing joint quality and improving deposition efficiency. Good weld joint with less porosity and excellent mechanical properties is obtained, which can reach as 92.62% tensile strength and 85.12% elongation percentage as base metal. Dimples in which the precipitated phase is the solid solution based on Al3Mg2 are observed in fracture scanning electron micrograph and the fracture mode is ductile rupture. α-Al and Al3Mg2 ,α-Al and eutectic structure are observed respectively in fusion area and in weld zone. The wire feed rate and melting rate can come to 14.5m/min and 80g/min respectively for the 1.6mm welding wire by the plasma-MIG welding process on the premise that the tensile strength of the joints meet the requirements.