The present invention relates to a composition for the treatment or prevention of a corneal injury, which comprises thymosin β4, and citric acid or its salt as active ingredients. The composition may further comprise at least one organic acid selected from acetic acid, ascorbic acid or salts thereof. The composition can maintain or increase the activity of thymosin β4 conventionally used to effectively treat wounds on the cornea, and thus, is useful as an ophthalmic formulation for treating the corneal injury.
