The invention belongs to the field of an energy material, and provides a lithium ion battery cathode material Bi2Mn4O10 preparation and an obtained product. The method comprises the following steps: 1) weighing a bismuth source and a manganese source according to a mole ratio being n(Mn)/n(Bi)=2; 2) performing wet-method ball milling; 3) drying obtained precursor slurry to obtain precursor powder;and 4) placing the precursor powder in roasting equipment, under air atmosphere, roasting the material for 3-10 h at the temperature of 600-800 DEG C. A traditional graphite material has the characteristics of small specific capacity and small volume ratio capacity. The lithium ion battery cathode material Bi2Mn4O10 can effectively solve the above problems. The preparation method has the advantages of simple process, low cost, safety and reliability, and friendly environment, the obtained lithium ion battery cathode material Bi2Mn4O10 has the advantages of large tap density and high purity, has high charge/discharge mass ratio capacity and volume ratio capacity, and good cycle stability.