The adsorption process is strongly dependent on the dielectric properties of the adsorbent. In this study, electrochemical impedance spectroscopy (EIS) was applied for measuring the dielectric characteristics of CO2 adsorption on hydrotalcite at 400 degrees C and atmospheric pressure. Compared with the gravimetric method measuring the kinetic properties at different CO2 pressures, EIS proved to be more effective for characterizing the CO2 adsorption process in situ with high sensitivity, distinguishing between physisorption and chemisorption. A model for the dielectric properties of hydrotalcite in the CO2 adsorption process was developed using the kinetic model of CO2 adsorption on hydrotalcite and dielectric mixture equation. The simulation results agree well with the experimental data, demonstrating the potential application of EIS in the study of CO2 adsorption on hydrotalcite.