To reduce polarization of electrochemical capacitor based on carbon nanotube, titanium oxide nanoparticles were deposited by ultrasound. The pore distribution of $TiO_2$/CNT nanoparticle exhibited surface area of $341;m^2g^{-1}$ when $TiO_2$ content was 4 wt %, which was better than that of pristine CNT with surface area of $188;m^2g^{-1}$. The analyses indicated that titanium oxide (particle diameter < 20 nm) was deposited on the CNT surface. The electrochemical performance was evaluated by using cyclic voltammetry (CV), impedance measurement, and constant-current charge/discharge cycling techniques. The $TiO_2$/CNT composite electrode showed relatively better electrochemical behaviors than CNT electrode by increasing the specific capacitance from $22;Fg^{-1}$ to $37;Fg^{-1}$ in 1 M $H_2SO_4$ solution. A symmetric cell assembled with the composite electrodes showed the specific capacitance value of $11;Fg^{-1}$ at a current loading of $0.5;mAcm^{-2}$ during initial cycling.