Complex resistivity is one of the important parameters for electromagnetic exploration in describing the electrical properties of underground rocks. Taking into account EM exploration frequency range, complex resistivity measurements in the laboratory are made as low as 10-2Hz. In order to avoid the influence to the study of rock’s microstructure by the electrode polarization of the macrostructure between electrode and rock, electrode polarization characteristic of different electrode materials to electrolyte and rock was used to investigate by electrochemical theory and complex resistivity experiment. The results show that test rock is easily affected by electrode polarization, which is dominated by material transfer, in the low frequency band, while electrode polarization is affected by the electrode material, salinity and temperature of fluid near the electrode, the measured rock impedance and other factors. Finally, the method to reduce or eliminate the effect of electrode polarization are analyzed and discussed, which provides the theoretical and experimental basis for accurately measuring complex resistivity and studying microstructure of rock.