Abstract: Tungsten inert gas (TIG) welding of 12 mm thick 5083 aluminum alloy plates was conducted using ER5356 filler wire. The results show that the microstructure in the weld, consisting of α-Al matrix and β-Al₃Mg₂ eutectic phase,was fine and homogeneous. The microstructure in the HAZ was slightly coarsened compared with the microstructure in the weld,and the microstructure in the base metal was fibrous along the rolling direction. The tensile strength of welded joints was over 90% of that of 5083 base metal. The welded joint had high strength and ductility,with good resistance to cold bending,fulfilling the standards of American bureau of shipping (ABS) and China classification society (CCS).