The invention discloses a Chinese medicinal lotion for treating eczema and a preparation method thereof. The Chinese medicinal lotion is prepared from the following raw materials in parts by weight: 15-20 parts of puffball, 10-15 parts of quassia root, 5-10 parts of herba aristolochiae, 10-15 parts of selinum japenious seed, 14-18 parts of Chinese brake herb, 16-22 parts of emblic leafflower leaf, 10-15 parts of acorus root, 5-10 parts of densefruit pittany root-bark, 15-20 parts of suberect spatholobus stem, 12-16 parts of herb of halfspreading ironweed, 16-22 parts of Chinese atractylodes, 15-20 parts of amur corktree bark, 18-24 parts of parslane herb, 6-12 parts of lightyellow sophora root, 10-15 parts of belvedere fruit, 14-18 parts of coptis root, 15-20 parts of rehmannia root, 11-17 parts of tung flower, 12-16 parts of figwort, 10-15 parts of plantain herb and 5-10 parts of Chinese buckthorn root bark. The Chinese medicinal lotion has the effects of clearing away heat, drying dampness, dispelling wind, arresting itching, astringing, promoting granulation, cooling blood and diminishing swelling, has a remarkable curative effect on various eczema, and has the advantages of quick response, short treatment course, good treatment effect, high curative rate, prevention of relapse, no toxic or side effect, no irritation, safety, convenience and low treatment cost.