The invention relates to a method for preparing spherical iron phosphate for lithium iron phosphate cell material. In the method, sheet iron, scrap iron, inorganic ferric salt, oxide of ferrum or organic iron is used for preparing ultra-pure high-density spherical iron phosphate for lithium iron phosphate cell material. Iron phosphate products produced by using the method have high main content of over 99.5%, extremely low impurity content, high dispersibility and high flowability, and oscillation ratios are all higher than 0.95; size distribution is in a narrow range, wherein D50 is stabilized at about 3 mum; the shapes of the products are shown to be sphere-like under an SEM (Scanning Electron Microscope), XRD (X-Ray Diffraction) also shows that the obtained iron phosphate products are pure phases, namely iron phosphate products with dehydrate structures. TG-DTA (Thermal Gravimetric-Differential Thermal Analysis) proves that iron phosphate produced by using the method disclosed by the invention is standard iron phosphate with two crystal waters.