Belonging to the technical field of Chinese medicine preparation methods, the invention relates to a preparation method of a Chinese medicinal lotion treating mustard preferring-type cellulitis. Current treatment of mustard preferring-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 sapindus mukurossi, Soda-apple Night-shade Herb, tartarian buckwheat roots and rhizomes, dandelions, Dysosma versipellis, Indian Stringbush Roots, Saururus chinensis, barberry roots, folium isatidis, garden euphorbia herb, Longhairy Antenoron Herb, Rohdea japonica roots, Aster ageratoides, Radix Sophorae Tonkinensis, Asarum sagittarioides, climbing groundsel herb, Huperzia Serrata, Japanese Stephania Roots, Thymifoious Euphorbia Herb, meadowrue roots and rhizomes, portulaca oleracea, Coriaria sinica leaves, Scutellaria baicalensis, Sedum sarmentosum, Sagina subulata, sugarcane, cottonrose hibiscus flowers, Sophora flavescens, bitter gourds, Folium llicis Latifoliae, Elephantopus scaber, polygonum cuspidatum, Saxifraga stolonifera, Polygonum hydropiper and licorice, etc., and putting the 39 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 mustard preferring-type cellulitis. The prepared Chinese medicine has the advantages of small toxic and side effect, short treatment course, and high curative rate.