The Cr₃₊ doped LiNi_0.5Mn_1.5O₄ cathode materials were successfully synthesized by solid-state method and the effect of doping amount into cathode material on its physical and electrochemical properties was studied. With the structure and morphology of cathode material characterized by X-ray diffraction and SEM, the results showed that the sample exhibited a pure spinel crystal structure. The effect of different Cr₃₊ doping amounts on the properties of LiCr_xNi_0.5-0.5xMn_1.5-1.5xO₄(x=0, 0.05, 0.1, 0.15, 0.2)cathode materials was discussed. The results of galvanostatic charge-discharge, CV and EIS test suggested that electrochemical properties of LiCr_0.1Ni_0.45Mn_1.45O₄ is the best when the Cr₃₊ doping amount is 0.1. At discharge rates of 0.1, 0.5, 1, 2, and 5C with the first specific capacities of 131.54, 126.84, 121.28,116.49 and 96.82mAh g_-1 respectively. At 1C rate after 50 cycles, its specific discharge capacity retention rate is 96.5%.