Disclosed are a drug for treating gastritis and a preparation method of the drug. The drug for treating gastritis comprises, by weight, from 13 to 17 parts of malt, from 8 to 12 parts of rhizoma picrorhizae, from 3 to 6 parts of frankincense and from 3 to 6 parts of myrrh. In the drug, the malt which is the monarch drug and the rhizoma picrorhizae which is the minister drug are integrated with the frankincense and the myrrh which are the assistant drug and the guide drug, the maximal treatment effect is realized, and effective rate of the drug is higher than 90% after the drug is verified by clinical tests of the Quanzhou Tao Zhaopei traditional Chinese medical clinic.