NOVELTY - Preparation of spherical lithium-iron phosphate cathode material involves mixing lithium carbonate, iron(II) oxalate dihydrate, ammonium phosphate and carbon black, adding ethanol, obtaining mixture, ball milling, heat treating, adding 3 g resultant heat-treated material into a reactor, adding 5.28 g ferrous sulfate, 0.8-4.58 g lithium dihydrogen phosphate and 10 ml deionized water, stirring, adding 0.5-1 g urea, mixing, carrying out hydrothermal reaction, obtaining reaction product, adding the obtained product into a reactor containing 5% sucrose solution, stirring, and sintering.    USE - Preparation of spherical lithium-iron phosphate cathode material used for high-power battery used as power supply for mobile phone, laptop computer, portable recorder, electronic toy, power tool, electric vehicle, hybrid vehicle and energy storage device.    ADVANTAGE - The method efficiently provides spherical lithium-iron phosphate cathode material having high density.    DETAILED DESCRIPTION - Preparation of spherical lithium-iron phosphate cathode material involves mixing lithium carbonate, iron(II) oxalate dihydrate, ammonium phosphate and carbon black in molar ratio of 0.5:1:1:0.3, adding ethanol solvent, obtaining mixture, ball milling the obtained mixture, obtaining slurry, performing spray drying of the obtained slurry, heat treating under protection of high-pure nitrogen atmosphere, adding 3 g resultant heat-treated material into a hydrothermal reactor, adding 5.28 g ferrous sulfate, 0.8-4.58 g lithium dihydrogen phosphate and 10 ml deionized water, stirring under magnetic force, obtaining transparent solution, adding 0.5-1 g urea, mixing uniformly, sealing the hydrothermal reactor, carrying out hydrothermal reaction at 200 degrees C for 10 hours, obtaining hydrothermal reaction product, adding the obtained hydrothermal reaction product into a reactor containing 5% sucrose solution, stirring under magnetic force, drying the resultant slurry, and sintering at high temperature under protection of high-pure nitrogen atmosphere.