The performance of LiNi_1/3Co_1/3Mn_1/3O₂ cathode material is improved by AlPO₄ nano-coating. AlPO₄-coated LiNi_1/3Co_1/3Mn_1/3O₂ is obtained by suspension solution of nano AlPO₄. Related characters are investigated by X-ray powder diffraction (XRD), scanning electron microscope imaging (SEM), transmission electron microscope imaging (TEM) and charge-discharge cycling test. The results show that the coating do not change the structure of LiNi_1/3Co_1/3Mn_1/3O₂, its surfaces are covered uniformly by nano AlPO₄, and the thickness of coating layer is about 4nm. To the electrochemical performance, AlPO₄-coated LiNi_1/3Co_1/3Mn_1/3O₂ is markedly improved capacity retention compared to pristine material upon cycling at 3.0- 4.5 V. Higher is the weight proportion of coating, better is the performance. However, high weight proportion of coating reduces the capacity. 0.2wt% coating is selected, because it not only improve capacity retention upon cycling at 3-4.5V, but also retain the best capacity of positive material.