The invention relates to a pharmaceutical composition for treating primary trigeminal neuralgia. The pharmaceutical composition is prepared from the following raw medicinal materials: scorpio, tortoise shell, semen cassia, rhizoma corydalis, dragon's blood, calculus bovis, fel ursi, adenophora tetraphylla, rhizoma nardostachyos, tendril-leaved fritillary bulb, radix polygonati officinalis, fructus viticis, cinnamon, marsdenia longipes, semen cuscutae and sea horse, wherein the scorpio, tortoise shell and semen cassia are taken as the monarch drug; the rhizoma corydalis, dragon's blood, calculus bovis and fel ursi are taken as the ministerial drug; the adenophora tetraphylla, rhizoma nardostachyos, tendril-leaved fritillary bulb, radix polygonati officinalis are taken as the adjuvant; and the fructus viticis, cinnamon, marsdenia longipes, semen cuscutae and sea horse are taken as the conductant drug. The pharmaceutical composition prescription for treating primary trigeminal neuralgia, disclosed by the invention, is simple in drug flavor, and the various flavors of medicines achieve respective effects, are coordinated with one another, and are compounded together to achieve unexpected technical effects in the aspect of treating the primary trigeminal neuralgia. At present, more than 300 patients of various kinds are cured, and the effective rate can reach 97% or higher. The pharmaceutical composition disclosed by the invention has the advantages of fast efficacy, high efficiency, short course of treatment, difficulty in reoccurrence and the like. In addition, the special four-quadrant preparation process is easy to master and apply.