Abstract: LiCoO2 powder as cathode material in lithium ion battery was synthesized by microwave heating using Co2O3 and LiOH·H2O as raw materials. The effects of microwave power output, heating time and holding time on the microstructure and composition of synthesized powder were investigated. XRD results show that the samples of single-phase layered LiCoO2 can be obtained with lattice constants confirming with reference values if the power output is 360 W and heating time and holding time are both 10 min. SEM images show that the LiCoO2 samples prepared under such conditions are featured with clear and smooth grain boundaries and evenly distributed grain size which is about 5 μm on an average. The microwave synthesis mechanism of LiCoO2 is discussed in combination with XRD results, indicating that the whole synthesis process is a two-step reaction. In addition, TGA-DTA tests were carried out for the raw materials.