Abstract: A numerical calculate model of alternating current(AC) power loss of clad materials with a rectangle section was presented.The effects of sectional form and configuration on the AC power loss of copper cladding aluminum(CCA) conductive flat bars were analyzed.The results indicate that when the sectional area of the bar is 600 mm²,the power loss coefficient increases with the width-to-thickness ratio of the bar increasing;when the area is 800 mm² or 1 000 mm²,the coefficient increases firstly then decreases;and when the area is 1 200 mm²,the coefficient decreases and the tendency becomes weak with the width-to-thickness ratio increasing.As the thickness of the bar is 10 mm and the sectional area of the bar is in the range of 800 to 1 200 mm²,the AC power loss decreases with the rate of copper thickness of the bar's narrow side to broadside increasing in the range of 0.5 to 3.0.The effect of the rate of clad thickness on the AC power loss strengthens as the rate of the copper layer's area to the whole sectional area of the copper cladding aluminum bar increases in the range of 15% to 45%.When the direct current resistance per unit length and current capacity are the same as a copper flat bar's,the AC power loss of the copper cladding aluminum bar is less than that of the copper bar by adjusting the sectional form and configuration.