Abstract: MnO↓2 used for electrode materials of super capacitor was prepared by sol-gel method.The product was characterized by X-ray diffraction and SEM.The results showed that the product was nano-sized α-MnO↓2 and its specific capacity was 146 F/g.The influence of additive dosage of Al↓2O↓3 on capacitive property and capacitance of MnO↓2 electrode material was investigated by doping different amount of Al↓2O↓3 into MnO↓2 during the calcination process.The experimental results indicated that the cyclic voltage-ampere characteristic of MnO↓2 electrode material was better after doping Al↓2O↓3.While dosing amount was 1％ (mass fraction of Al↓2O↓3)，the electrode material could attain the highest specific capacity of 165 F/g，and after 200 cycles of constant charge-discharge，the electrode was stable and its capacitance still kept more than 90％.