Abstract: Cobalt chemically doped MnO₂ used as electrode materials for supercapacitors were preparedby chemical co-precipitation method. The result of XRD shows that the values of doped Co affect the crystal structure and electroactive property of these materials. The electrochemical measurements show that the ratios of cobalt have great influence on their electrochemical capacities. When the mole ratio of n（Co）:n（Co+ Mn） is higher or lower than 0.1, their electrodes present the worse charge-discharge properties and capacity. The electrode doped with Co has better capacity property,low impedance and high usage rate, and can be charge-discharged at high current of 40mA. After 1000 cycles, specific capacitance of modified MnO₂ electrode is higher than that of MnO₂ electrode, but its cycling charge-discharge property is relatively worse.