The invention relates to an aluminum alloy welding wire for aerospace and a preparation method of the aluminum alloy welding wire for aerospace. The aluminum alloy welding wire for aerospace is characterized by comprising the following chemical components in percentages by mass: 6.2-7.0% of Cu, 0.06-0.10% of Ti, 0.1-0.5% of Cr, 0.05-0.2% of V, 0.1-0.5% of Mn, 0.5-1.5% of Sc, 0.05-0.2% of Te, 0.01-0.05% of Bi, less than or equal to 0.2% of Mg, less than or equal to 0.2% of Fe, less than or equal to 0.2% of Si, less than or equal to 0.05% of single content of other impurity elements, less than or equal to 0.15% of total content of other impurity elements and the balance of Al. The preparation method of the aluminum alloy welding wire for aerospace comprises the following steps: smelting, refining, casting, homogenization, extrusion, drawing, and surface treatment. The aluminum alloy welding wire for aerospace provided by the invention is fine in weld microstructure and good in crack resistance; the tensile strength, the plasticity and the toughness of welded joints are remarkably higher than those of common 5556, 5654, 2319 or 2325 welding wires.