The invention discloses a novel Chinese medicinal composition for treating eruption and a preparation method thereof. The Chinese medicinal composition mainly comprises the following raw material medicaments: fineleaf schizonepeta herb, divaricate saposhnikovia root, weeping forsythia, taraxacum officinale root, mint, great burdock achene, cicada slough, kudzu-vine root, bupleurum, mulberry leaf, chrysanthemum, gypsum, anemarrhena asphodeloides bunge, Mongolian snakegourd root, common lophatherum herb, baical skullcap root, densefruit pittany root-bark, lightyellow sophora root, ash bark, raw rehmannia root, figwort root, tree peony bark, sinkiang arnebia root, honeysuckle flower, violet, natural indigo, cortex lycii radicis, bunge cherry seed, glabrous greenbrier rhizome and the like. The Chinese medicinal composition can be prepared into any common oral preparation by the conventional Chinese medicinal preparation method. The Chinese medicinal composition can obviously improve symptoms such as rubella, measles, damp sore, medicinal toxin, prickly heat toxin, scabies, popular urticaria, universal eczema, premenstrual urticaria, gestational rubella and the like. The Chinese medicinal composition has the advantages of exact clinical effects, obvious curative effect, quick response, low cost, basically no toxic or side effects and the like.