In this study, LNMO materials with different Al3+ doping amount were prepared. The structure of Li1+xAlxNi0.5Mn1.5-xO4 was characterized by XRD and SEM. The electrochemical properties of the materials were determined by CV test and AC impedance spectroscopy. Discussed the influence of the doping amount of Al3+ on various aspects of the material. Studies have shown that proper doping increases the structural stability of the material and improves the cycle and rate performance of the material. The modification effect was best when the doping amount was x=0.06, and the retention rates of circulating 100 times at 0.5C and 2C reached 95.2% and 90%, respectively. Moreover, the potential difference of the redox peak is small, and the cycle reversibility is the best. The samples prepared by the polymer-assisted method further improved the cycle performance due to the stronger orientation of the {111} crystal face group, and the 100-time retention rate at 0.5C and 2C reached 97.1% and 93%, respectively.