Abstract: Specimens of cathode material LiCoO2 for lithium ion battery were prepared by microwave synthesis to investigate the microstructure, morphology and electrochemical behaviors by means of XRD, SEM and DC-5C battery tester. The results show that a high-purity layered LiCoO2 can be obtained just in a 10-min reaction process at 900 W and 2.45 GHz, The charging capacity is up to 140 mAh/g, and both the platform charging curve and time for charging/discharging demonstrate the electrochemical activity of the microwave synthesized LiCoO2. Testing experimentally the effect of the molefraction of Li to Co on the microstructure of specimens, the optimal Li/Co molefraction should be 1.05/1.