The invention discloses a drug for treating tinea pedis. The drug is made from the following raw materials based on parts by weight: 0.5-1.0 part of Chinese gall, 0.1-0.5 part of common cnidium fruit, 0.1-1.0 part of flavescent sophora root, 25-30 parts of salicylic acid, 1.0-5.0 parts of glacial acetic acid, 100-150 parts of carbolic acid and 8-12 parts of alcohol. The invention further discloses a preparation method of the drug for treating the tinea pedis, which comprises the following steps: a. the Chinese gall, the common cnidium fruit and the flavescent sophora root are weighed according the parts by weight, soaked in 90-95% of the alcohol for 12-18 days and filtered to obtain filtrate; b. the salicylic acid, the glacial acetic acid and the carbolic acid are weighed according to theparts by weight and added to the filtrate from the step a and evenly mixed. The drug can effectively relieve symptoms of the tinea pedis, beriberi, smelly feet and the like, has no obvious adverse reaction and toxic and side effect, and reaches 98% in terms of the total effective rate. As the drug combines the Chinese traditional medicine and the western medicine, the drug has little irritation to skin and good curative effect, can cure years of stubborn diseases after a single use, and has no repeated attack after use; in addition, the drug has simple formula, available drug source and simple preparation method, and is suitable for large-scale popularization.