The invention discloses a composition for treating herpes zoster and a preparation method thereof. The composition for treating the herpes zoster is prepared from the following raw materials: coptis root, radix scutellariae, phellodendron amurense, rhubarb, radix geutianae, alkanet, radix paeoniae rubra, Chinese angelica, indigo naturalis, giant knotweed, fructus forsythiae and gardenia. Aiming at the pathogeny and the pathogenesis of forming the herpes zoster, active components of various Chinese medicaments have synergistic reactions to treat the herpes zoster by clearing heat and detoxication, eliminating dampness and alleviating pain, absorbing clots and relieving internal heat, removing the necrotic tissue to promote tissue generation, and the sequelae of scars, neuralgia and the like are not generated. The composition for treating the herpes zoster can be prepared into any common oral dosage form or external preparation and has remarkable curative effect on the herpes zoster, and the total effective rate can reach 100 percent; besides, aiming at the pathogenic mechanism of the herpes zoster and improving the immunity of organisms, the composition treats both principal and secondary aspects of a disease, has short course of treatment and high curative effect, and has no side effects on human bodies.