he phase structure, the morphology, activation performance and cycle stability of the rare-earth-doped lithium manganese oxygen cathode materials prepared by Pechini process were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and battery testing system. The results show that the prepared LiMn2O4, LiLa0.03Mn1.97O4, LiLa0.012Ce0.012Mn1.976O4, LiLa0.012Nd0.012Mn1.976O4 and LiCe0.012Nd0.012Mn1.976O4 samples are composed of single-phase spinel LiMn2O4 structure only when the content of rare earth is strictly controlled in a certain range. The LiLa0.015Ce0.015Mn1.97O4, LiLa0.015Nd0.015Mn1.97O4 and LiCe0.015Nd0.015Mn1.97O4 specimens consist of the LiMn2O4 and trace CeO2, Nd2O3, CeO2+Nd2O3 phases when the content of the rare earth exceeds the range. The particles of all the specimens are regularly spheroid or near-sphere, and the size of the particles is 0.5-2.8 μm. The initial discharge capacity of the specimens would be decreased, and the ratio of discharge/charge capacity and cyclic stability of the specimens would be increased with the suitable rare earth element doping. The LiCe0.012Nd0.012Mn1.976O4 cathode materials has good comprehensive electrochemical performances whose initial discharge capacity is 123.5 mAh/g, and whose capacity is 113.2 mAh/g after the 30th cycle, 1.27 times as high as that of LiMn2O4 material