Abstract: On the base of reparation of pure lithium cobalt oxide, the LiRE_xCo_1-xO₂ are prepared by doping rare earth such as La, Ce, Lu, Y into LiCoO₂ with precipitation method.The structures are characterized by means of XRD and SEM, the electrochemical characterization are tested also.The results shows that the prepared materials doped with La, Ce, Lu and Y shows the structure of LiCoO₂.When the addition of La is less than 0.05, the rare earth can transform into single LiRE_xCo_1-xO₂ phase completly.The doped rare earth can promote LiRE_xCo_1-xO₂ crystallization and make the intensity of LiCoO₂ in 104 diffraction increase.The LiRE_xCo_1-xO₂ have high reversibility of electrochemistry and the first discharge are 147.4 mAh/g.