Belonging to the technical field of Chinese medicine preparation methods, the invention relates to a preparation method of a Chinese medicinal lotion treating dark urine-type cellulitis. Current treatment of dark urine-type cellulitis generally employs antibiotics and sulfonamides, and has the disadvantage of great side effect. A technical scheme adopted by the invention consists of: taking Polyporus, Rhizoma Dioscoreae Hypoglaueae, coix seeds, waxgourd peels, Phaseolus calcaratus, Zanthoxylum bungeanum Maxim, Corn Stigma, gourds, Commelina communis, Polygonum aviculare, Dianthus superbus, akebia stems, Ricepaperplant Pith, Juncus effusus, Patience Dock Roots, Ilex pubescens, Herba Patriniae, Changium smyrnioides, Hemsleya macrosperma, Anemarrhena asphodeloides, radix tinosporae, Trollius chinensis, honeysuckle, Bidens biternata, houttuynia cordata, Herba Lespedezae Cuneatae, hypericum perforatum, Sedum sarmentosum, Sagina subulata, convallaria majalis and licorice, and placing the 31 medicines into water for immersion, then conducting decocting with slow fire, and carrying out filtration to remove the residue, thus obtaining a liquid medicine, i.e. the Chinese medicinal lotion treating dark urine-type cellulitis. The prepared Chinese medicine has the advantages of simple preparation, small toxic and side effect, short treatment course, and high curative rate.