To provide an easy and practical iron ion removal method, as a method for purifying P, P-di (uridine 5'-)tetraphosphate from a solution containing iron ions.Purification is performed by a purification method includinga method for purifying P, P-di (uridine 5'-)tetraphosphate by removing iron ions from an aqueous solution or hydrophilic solvent solution containing P, P-di (uridine 5'-)tetraphosphate and iron ions, including(1) a step of purification using a chelating resin packed column, and(2) a step of adjusting the pH of the solution after said purification step using the chelating resin packed column to 5.5 or less, and then crystallizing P, P-di (uridine 5'-)tetraphosphate, ora step of treating the solution after said purification step using the chelating resin packed column with zinc chloride-activated activated carbon.
