LiFeO2, with a layered rocksalt structure of alpha-NaFeO2-type was prepared by ion exchange reaction from Na+ ion to Li+ ion using alpha-NaFeO2. alpha-NaFeO2-type LiFeO2 was synthesized by using the mixture of LiI and KI in the temperature range 220 to 480 degrees C. The heat treatment temperature of 600 degrees C gave alpha-LiFeO2-type LiFeO2 as a main product. As a result of Rietveld analysis, the structure of LiFeO2 which assigned to alpha-NaFeO2-type by an XRD measurement, was the mixture of alpha-NaFeO2-type and Li-intercalated spinel-type structures.