A lithium-rich layered cathode material Li1.2Mn0.54Ni0.13Co0.13O2 with high specific capacity and good cycle stability was successfully synthesized by a modified sol-gel method. The Li element was replaced by Al, and Li1.16Mn0.54Ni0.13Co0.13Al0.04O2 material with better performance was obtained. Characterized and observed by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Al substitutedmaterial not only has a good crystal structure and a layered structure but also improves structural stability. The electrochemical results show that Al-substitution Li1.16Mn0.54Ni0.13Co0.13Al0.04O2 material has good electrochemical performance. The initial discharge capacity at room temperature is 271 mAh/g in the potential range of 2.0-4.8 V at 0.1C rate. Even at high rates of 0.5C and 2C, the material provides 185 mAh/g and 156.1 mAh/g capacity, with capacity retention rates of 85.2% and 87.3% after 200 cycles, respectively. Therefore, the positive electrode material synthesized by the sol-gel method after doping Al may be an efficient method for replacing the electrode material.