The effect of niobium ion with high valence doping on high voltage LiNi0.5Mn1.5O4 materials was investigated. LiNi0.5Mn1.5-xNbxO4 was prepared by doping high-valent niobium ion into LiNi0.5Mn1.5O4 material using the organic assisted combustion method. The experimental samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical impedance analysis. The experimental results show that the doping with high valence niobium ion change the orientation of the crystal plane growth of spinel particles, and the morphology of these particles change from the octahedral shape before doping to the spherical shape after doping. With the increase of doping amount, the crystal structure changes gradually, resulting in the Li0.96Nb1.01O3 impurity phase. The doping of high valence niobium ion increases the content of Mn3+ in the material, resulting in the appearance of a 4 V discharge platform, and the formation of a 4.7 V and 4 V discharge platform. The doping of Nb can improve the cycling stability of LiNi0.5Mn1.5O4 material, but the specific capacity of the material is reduced.