The invention relates to a production method for high-purity ferric phosphate. Ferrous sulfate solution dissolved by a raw material, i.e., iron sulfate heptahydrate crystal used for producing ferric phosphate or ferrous sulfate solution generated by the reaction of iron and sulfuric acid is subjected to three-time impurity-removal and purification processing; the purified ferrous sulfate solutioncarries out oxidation reaction with hydrogen peroxide to generate ferric sulfate solution; under the condition of emulsifier, phosphate solution is dripped to react to synthesize ferric phosphate precipitates, or phosphoric acid is added into the purified ferric sulfate solution; after evenly mixing, hydrogen peroxide is added for oxidation, emulsifier is added, and ferric phosphate precipitates are synthesized; then, the ferric phosphate precipitates are aged, rinsed, filtered and dried to prepare aqueous or anhydrous high-purity ferric phosphate. The synthesized high-purity ferric phosphatehas an impurity index that potassium, sodium, calcium, magnesium and manganese are less than 50ppm, titanium and aluminum are less than 20ppm, and heavy metal ions, i.e., cobalt, nickel, zinc, copper,lead, chromium are less than 5ppm. By use of the production method, the problems of low purity and more impurity of a product obtained in the prior art are overcome.