The T2 copper and 1060 aluminum alloy foil are spiral spot welded by a nanosecond laser and the galvanometer system. The weld formation and the microstructures under different overlapping combination modes are analyzed. The results show that for the overlapping combination mode in which aluminum is on the top of copper, the metal on the aluminum side is completely melted, and in some areas, aluminum penetrates into the copper substrate and the “V” shaped tiny welds are formed. In contrast for the overlapping combination mode in which copper is on the top of aluminum, the weld is composed of tiny welds with high aspect ratios. Under these two overlapping combination modes, there exist four typical areas of γ2-Cu9Al4, hypereutectic structure, eutectic structure, and hypo eutectic structure within the microstructure of welds. The CuAl2 intermetallic compound layer is thin and no obvious cracks are found at the joint interface. The brittleness of joints is obviously improved.