TiO_2paste was prepared by hydrothermal method for 5h at 220℃.The modified electrode was obtained by dipping TiO_2electrode into 15% La(NO₃)_3solutio n during different periods of time (15min,30min,45min,60min),followed by sin tering in air at 450℃ for 20min.The main components and morphology of the modified electrode are characterized by X ray photoelectron s pectroscopy (XPS) and scanning electron microscopy (SEM).The current-voltage (I-V) curves are measured using AM1.5G solar simulator and electrochemical workstation (CHI660e) with incident l ight power calibrated to 100mW/cm².Electrochemical impedance spectroscopy (EIS) characteristics of the dye-sensitized solar cells (DSSCs) are performed with impedance analyzer in a two-electrode configuration in the dark (－0.1～ 1V bias potential,0.01~100kHz frequency,10mV modulation signal).The results show the modified electrode has two layers:the surface coating layer with larger particle size is La₂O_3and the lower layer with smaller particle size is TiO₂.The current-voltage (I-V) curves show that the open circuit voltage and short circuit current of the optimal modified electrode are enhance d by 6.8% and 18.5%,respectively.EIS test results show that the interface recombination resistance of TiO₂/La₂O_3electrode is larger than that of T iO_2electrode at the same bias,which indicates that the La₂O_3coating laye r can inhibit the electron recomb ination at the interface and improve the photoelectric chemical properties of cells.