The invention discloses a preparation method of hollow lithium manganese phosphate nano balls. The preparation method comprises the following steps: mixing ethylene glycol and water according to the volume ratio of 1 to (1-2) to obtain a mixed solvent; mixing one part of the ethylene glycol/water mixed solvent with manganese sulfate to obtain a mixed solution I with the concentration of 0.0625M-0.125M; mixing part of the ethylene glycol/water mixed solvent with lithium sulfate and ammonium dihydrogen phosphate to obtain a mixed solution; agitating the mixed solution uniformly and adding KOH; continually agitating to obtain a mixed solution II, wherein the concentration of lithium sulfate in the mixed solution II is 0.125M-0.1875M, the concentration of the ammonium dihydrogen phosphate in the mixed solution II is 0.083M-0.125M and the concentration of potassium hydroxide in the mixed solution II is 0.375M-0.4375M; and adding the mixed solution I into the mixed solution II, agitating uniformly and carrying out hydrothermal reaction to obtain the hollow lithium manganese phosphate nano balls, wherein the volume ratio of the mixed solution I to the mixed solution II is (1-1.2) to 1. The method for preparing the hollow lithium manganese phosphate nano balls is obtained by accurately controlling a feeding sequence and reaction conditions.