Provided is a simple and practical method for removing iron ions, as a method for purifying P1,P4-di(uridine 5'-)tetraphosphate from a solution that contains iron ions. This method for purifying P1,P4-di(uridine 5'-)tetraphosphate by removing iron ions from an aqueous solution or hydrophilic solvent solution containing P1,P4-di(uridine 5'-)tetraphosphate and iron ions includes: (1) a column purification step that uses a chelate resin, and (2) a step for adjusting the pH of the solution to 5.5 or less following the chelate resin column purification, and then crystallizing P1,P4-di(uridine 5'-)tetraphosphate； or a step for treating the solution with zinc chloride-activated activated carbon following the chelate resin column purification.
