The invention discloses dynamic lithium manganate applied to an anode material of a lithium ion battery and a preparation method of dynamic lithium manganate. Lithium manganate has the normal-temperature 1000-cycle 1C cyclic capacity retention ratio of not less than 80% and the high-temperature 200-cycle 1C cyclic capacity retention ratio of not less than 80%. The preparation method comprises the following steps: using electrolytic manganese dioxide and lithium carbonate as raw materials, mixing according to a lithium-to-manganese molar ratio of 0.54 to 0.58, baking a mixture in a baking furnace, and performing furnace cooling; adding an additive in the sintered product for secondary mixing, re-sintering a secondary mixture in the baking furnace, performing furnace cooling to obtain a primary product, and enabling the primary product to pass through a 200-mesh standard sieve to obtain dynamic lithium manganate. Dynamic lithium manganate is good in cyclic performance and high-temperature performance, and can be applied to electric two-wheeled vehicles or sightseeing vehicles; the preparation method is simple, the preparation process is easy to control and operate, and the production cost is low.