The A-site La0.33NbO3 perovskite was prepared by a solid-state reaction at high temperature. A superstructure was observed in both the XRD and electron diffraction patterns of La0.33NbO3, which is related to the ordering of La3+ ions and vacancies in the A sites. The La0.33NbO3 was used as the electrode material in lithium cells. Approximately 0.67 lithiums can be electrochemically inserted per La0.33NbO3 formula, which confirms the structural analysis. The kinetic process of lithium insertion/extraction in a La0.33NbO3 electrode was determined by electrochemical impedance spectroscopy (EIS). he charge-transfer resistance (R-CT) decreases and the diffusion coefficient increases with lithium insertion into La0.33NbO3 structure.