NOVELTY - Preparing submicron battery level ferric pyrophosphate comprises dissolving iron salt compound in deionized water to obtain a iron salt aqueous solution (0.1-4 mol/l), adding an oxidizing agent to the iron salt solution to convert divalent iron into trivalent iron, dissolving phosphorus source compound in deionized water to obtain phosphate aqueous solution (0.1-4 mol/l), preparing dispersant aqueous solution, stirring and reacting phosphate aqueous solution, iron salt solution and dispersant aqueous solution, completing reaction, separating reactants, washing and drying to obtain the product.    USE - The method is useful for preparing submicron battery level ferric pyrophosphate.    ADVANTAGE - The method is simple in operation, easy to control, produces product with small and uniform particle size by controlling the reaction conditions, and is suitable for industrial production.    DETAILED DESCRIPTION - Preparing submicron battery level ferric pyrophosphate comprises: (i) dissolving iron salt compound in deionized water to obtain a iron salt aqueous solution (0.1-4 mol/l), where the iron salt compound is ferrous sulfate, ferrous chloride, ferric sulfate, ferric chloride and/or ferric nitrate, adding an oxidizing agent to the iron salt solution to convert divalent iron into trivalent iron, and controlling the pH of the aqueous iron salt solution to 2-6 and temperature at 10-900 degrees C; (ii) dissolving phosphorus source compound in deionized water to obtain phosphate aqueous solution (0.1-4 mol/l), where the phosphorus source compound is phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate and/or ammonium dihydrogen phosphate; (iii) preparing dispersant aqueous solution (0.01-4 wt.%), where the dispersant is citric acid, polyethylene glycol, sodium dodecyl benzene sulfonate, fatty acid glyceride, fatty acid sorbitan and/or polysorbate; (iv) slowly adding the prepared phosphate aqueous solution and iron salt solution into the dispersant aqueous solution, where the reaction concentration of phosphorus source compound and iron salt compound is 8-25%, adjusting the pH of the reaction mixture to 2-6 using phosphoric acid or ammonia, stirring at a rate of 100-160 revolutions/minute, and reacting at 10-90 degrees C for 120-480 minutes; and (v) completing the reaction, separating reactants, washing and drying to obtain the product.