Abstract: Aluminum alloy 5A06 ultrathin plates with thickness of 0.8 mm were welded by advanced cold metal transfer welding process, and the forming quality, microstructure and tensile properties of the welded joint were studied. The results show that the weld was well formed, continuous and beautiful, without defects such as porosity, crack and inclusion when the front shielding gas flow rate was 20 L·min^-1, the back shielding gas flow rate was 5 L·min^-1, the welding current was 75-80 A, and the welding speed was 1 000 mm·min^-1. The microstructure of the base metal of the joint was composed of rolled elongated α-Al phase and dispersion strengthening phase distributed at the grain boundary; the microstructure of fusion line, heat affected zone and weld was equiaxed grains. The joints fractured at the base metal after tension. The tensile strength was about 360 MPa, and the elongation percentage after fracture was about 12%, indicating the joint had excellent tensile properties. There were a lot of dimples in the fracture, and ductile fracture occurred in the joint.