The invention discloses a medicine special for treating spasm of hemiplegic patients and a preparation method thereof, wherein the medicine comprises the following medicine raw materials: Lycopodiastrum casuarinoides, large-leaved gentian, Passiflora wilsonii, Gaultheria yunnanensis, thin evodia leaf, Rhizoma Dioscoreae Nipponicae, uncaria, dandelion, trichosanthes palmata, Argyreia acuta Lour, Capparis bodinieri, edgeworthia chrysantha, lamprey, russula rubra, shinyleaf pricklyash root, Ophiorrhiza succirubra King, dog kidney, illicium verum, fructus psoraleae, nutgall, ram testes, frog, aspongopus, radix aconiti sinensis, Orobanche coerulescens, radiate bulbophyllum herb, limonium bicolor, motherwort fruit, white paeony root, conic gymnadenia tuber, peach gum, aralia root, siphon and achyranthes aspera. The medicine special for treating spasm of hemiplegic patients has the effects of relaxing tendon, activating collaterals, warming yang, invigorating kidney, tonifying qi, promoting blood circulation, relieving stagnation and clearing damp. As for treatment on spasm of hemiplegic patients, the medicine special for treating spasm of hemiplegic patients effectively improves the spasm symptom by utilizing the traditional Chinese medicine theory, paying attention to the overall view and regulating the human body, and is safe and effective, convenient to take, good in curative effect and quick in response; the spasm is difficult to recur; the medicine has no side effect; patients can accept the medicine easily; and clinical market development can be performed.