The invention discloses medicine for treating allergic rhinitis and a method for preparing the medicine. The medicine comprises, by weight, 16-20 parts of astragalus, 14-16 parts of fried fructus xanthii, 14-16 parts of flos magnoliae, 10-14 parts of bighead atractylodes rhizome, 8-12 parts of angelica dahurica, 10-14 parts of cicada slough, 6-10 parts of salvia miltiorrhiza, 6-10 parts of licorice, 11-13 parts of sucrose powder and 1-3 parts of dextrin which are manufactured into grains. The method includes extracting volatile oil, mixing raw materials; adding the raw materials into water and soaking the raw materials in the water; and decocting the raw materials in the water, and the like so as to obtain a finished product. The medicine and the method have the advantages that the medicine is granular preparation, can be taken conveniently, is portable, is low in cost and can realize effects of tonifying qi, strengthening exterior, dispelling coldness, eliminating pathogens, dredging channels and promoting blood circulation, symptoms such as nasal obstruction, rhinocnesmus, sneezing and rhinorrhoea caused by the allergic rhinitis can be effectively improved, a curative effect is persistent, and the total effective rate can reach 90% at least as shown by observation for clinical effects.