Abstract: Hot extruded Al-12.7Si-0.7Mg alloy plates were welded by tungsten inert gas (TIG) welding method using imported ER4043 and ER4047 welding wire. The microstructures and mechanical properties of welded joints were studied by optical microscopy, microhardness test and tensile test methods. The results showed that weld beads are fairly good under the chosen welding parameters. The weld zone (WZ) is the typical casting structure formed during weld solidification. Coarsening of silicon phase was observed in the heat-affected zone (HAZ). The distribution of microhardness of the welded joints shows that the hardness gets maximum values in WZ, drops rapidly in fusion zone (FZ) and reaches to minimum values at HAZ. The tensile strength of the joints welded with either ER4043 or ER4047 welding wire reach more than 90% of the base material.