The invention belongs to the field of traditional Chinese medicine preparation, and particularly discloses a medicine for treating skin diseases, a preparation method and preparations. The medicine for treating the skin diseases is prepared from the following materials in parts by weight: 50 to 150 parts of radix rhamnius crenatae, 25 to 75 parts of henry chloranthus herb, 25 to 75 parts of cochinchina momordica root bark, 50 to 150 parts of ginkgo biloba exocarp, 25 to 75 parts of ginkgo root bark, 20 to 40 parts of common cnidium fruit, 20 to 40 parts of Chinese gall and 10 to 30 parts of pricklyash peel. By adopting the Chinese medicinal material composition with definite efficacy on skin tinea, the different external preparations can be prepared according to clinical requirements, andare convenient to use. The medicine for treating skin diseases has a strong antibacterial effect, is also comfortable when being applied, and can quickly relieve dryness and itching and effectively treat skin diseases, such as dermatitis, neurodermatitis, scabies, acnes, versicolor pityriasis, tinea of feet and hands, onychomycosis, tinea versicolor, tinea corporis and tinea cruris, moreover, themedicine for treating the skin diseases has a good astringent, anti-exudation, pain-relieving and itching-relieving effect on erosive inflammations infecting focusi, and therefore the medicine for treating skin diseases is an ideal medicine for treating skin diseases, such as dermatitis, scabies and tinea.