Abstract: Disclosed is a method for refining 5-fluorouracil, comprising the following steps: dissolving 5-fluorouracil in an organic solvent, preferably DMSO, heating and stirring until dissolved; naturally cooling the filtrate until a crystal is precipitated; filtering, washing a filter cake using a polar solvent, and draining and drying under reduced pressure. By using the new refining method, the content of impurities in 5-fluorouracil may be reduced to less than 0.01%, the product purity is more than 99.98%, and the refining yield is higher than 70%. In addition, the refining method of the present invention has a simple process, convenient operation, low production costs, high product purity, a stable process, and is suitable for industrial production.