Hydrotalcite was synthesized from hydroxide-form precursors to prepare a novel high-temperature CO2 sorbent, and the effect of Mg/Al ratio on CO2 sorption was studied. To enhance the CO2 sorption capacity of the sorbent, K2CO3 was coprecipitated during the synthetic reaction. X-ray diffraction analysis indicated that the prepared samples had a well-defined crystalline hydrotalcite structure, and confirmed that K2CO3 was successfully coprecipitated in the samples. The morphology of the hydrotalcite was confirmed by scanning electron microscopy, and N2 adsorption analysis was used to estimate its surface area and pore volume. In addition, thermogravimetric analysis was used to measure its CO2 sorption capacity, and the results revealed that the Mg : Al : K2CO3 ratio used in the preparation has an optimum value for maximum CO2 sorption capacity.