The invention discloses a medicine for treating rheumatoid arthritis and a preparation method thereof. The medicine comprises the ingredients of Chinese parsnip root, glabrous sarcandra herb, berba aristolochiae mollissimae, erycibe obtusifolia benth, Chinese Starjasmine Stem, tuber fleeceflower stem, Chinese Ivy Stem and the like which are called 'Three-Feng Four-Teng Soup'. The preparation method comprises the steps of cleaning, soaking, decocting and the like, all the raw materials are used in combination, and all the medicines cooperate in effects to effectively treat rheumatoid arthritis and effectively control the relapse of rheumatoid arthritis. The medicine for treating rheumatoid arthritis has the functions of suppressing fungi, dispelling wind to eliminate dampness, activating blood circulation to dissipate stasis, eliminating stagnation to stop pain, and clearing and activating the channels and collaterals, is high in efficiency and cure rate when used for treating rheumatoid arthritis, has no toxic and adverse effects and good safety, and is easy to prepare, low in cost and price and suitable for patients.