This paper deals with the electric and thermal characteristics of the composite busbar composed of aluminum and copper. When AC current is flowing in Cu busbar used widely in conservative equipments like power cable, transformer, and switchgear & controlgear most current is concentrated on the surface of the busbar by the skin effect. Therefore, if the Cu region in the busbar having low current density is replaced with aluminum, we can largely reduce the product cost and weight of the busbar. To conform the performance of the composite busbar, we designed and fabricated a test Al/Cu composite busbar. Maximun temperature rise of the busbar was $35^{circ}C$ when 1600 Arms of AC current was applied to the test composite busbar($120mm{ imes}10mm$). Based on test results, we can expect to make the low-priced and light power equipments using the Al/Cu composite busbar.