The invention discloses a preparation method of a Chinese medicinal lotion for treating spleen deficiency ecthyma, belonging to the technical field of Chinese medicine preparation methods. At present, antibiotics and sulfanilamide are generally adopted for treating spleen deficiency ecthyma. If cefoperazone is adopted, partial intramuscular pain can be caused, allergic reactions such as erythra and medicament fever occur occasionally, and reduction in complete blood cells, prolonging in prothrombin time or bleeding and the like can occur on individual patients. According to the technical scheme of the invention, the method comprises the following steps of: putting 31 medicaments including cabbage, dried longan pulp, large-head atractylodes rhizome, white paeony root, American ginseng, Chinese angelica, lotus seed, dangshen, sharpleaf galangal fruit, astragalus, sealwort, polished round-grained rice, dried ginger, wild pepper, medicinal evodia fruit, common monkshood mother root, aconitum carmichaeli debx, prepared common monkshood daughter root, wild ginger, pepper, long pepper, piper cubeba, fennel, chive, Chinese ginger, selinum japenious seed, hot pepper, caraway, resurrection lily rhizome, black-bone chicken and liquoric root into water for soaking; and decocting with soft fire to obtain a decocted medicinal liquid which serves as a Chinese medicinal lotion for treating spleen deficiency ecthyma. The Chinese medicinal lotion has the advantages of small toxic and side effects of a prepared Chinese medicine, short treatment course and high curative rate.