The invention discloses a spray for treating radioactive xerostomia and a preparation method thereof. The spray is prepared by adding a plurality of plant extracts based on the conventional artificial saliva and has a cool sweet taste and a plurality of effects, such as diminish inflammation, antibiosis, tooth cleaning, whistle wetting and the like. Compared with the conventional artificial saliva, the spray of the invention has the advantages that: because menthol, momordica glycosides V and stevioside A are added in the formula of the spray, the product has the cool sweet taste and patients enjoy in mouthfeel, and by fully meeting the requirements of the patients with diabetes, obesity and the like, disadvantageous consequences probably caused by a sweetener contained in the product are avoided; because a Chinese globeflower extract, a liquorice root water extract, a wild chrysanthemum water extract and a perilla water extract are added in the spray, the product has the cool sweet taste and also the plurality of effects, such as diminish inflammation, antibiosis, tooth cleaning, whistle wetting and the like, and contributes to the maintenance of oral hygiene and the prevention of oral infection; and because the using times is a few, the spray contributes to the effective remission of thirst.