By changing the mass ratio of resorcinol, formaldehyde and sodium carbonate, the pore structure of carbon aerogel was controlled and by changing the highest temperature of CO₂ activation, the effects of activation temperature on the pore structure and electrochemical performance were studied.The pore structures and morphologies of carbon aerogel were investigated by using N₂ adsorption isotherms(BET) and scanning electron microscopy(SEM).The electrochemical performances of carbon aerogel were characterized by virtue of the cyclic voltammetry(CV), and galvanostatic charge-discharge test.The results show that the increase of activation temperature is helpful to improve the materials' structure and performance.When the highest temperature of CO₂ activation reaches 1000℃, carbon aerogel will have the highest specific surface area(2201 m²/g), and the specific capacitance of the corresponding electrode in 6 mol/L KOH electrolyte will be about 190 F/g with a current density of 1 A/g.