A method for producing the flocculant polyferric chloride, wherein iron ore powder or waste iron wire is subjected to mixed acid leaching with sulfuric acid and hydrochloric acid, and the pH value is adjusted to produce this product; in this product, the mixed acid is used for acid leaching, the reaction speed is fast, the method of adjusting the pH value is used to separate the viscous gel generated by acid leaching with sulfuric acid, which saves the energy required for concentration due to dilution separation, does not destroy the structural water in the molecule, and increases in the molecule.