The invention discloses a medicament for preventing and treating hypertension, which relates to a Chinese herbal medicine, in particular to a medicament for preventing and treating hypertension. The medicament is mainly used for treating liver yang hyperactivity type vertigo, tinnitus, fullness and pain in the head, head heaviness, foot lightness, flushed face, congested eyes, impetuosity, irritability, insomnia or dreaminess, soreness and weakness of waist and knees or dysphoria in chestpalms-soles caused by various reasons, and is suitable for treating symptoms of hypertension. The medicament consists of the following bulk pharmaceuticals by weight: 50-65g of cassia seed, 25-35g of common selfheal fruit-spike, 25-35g of chrysanthemum and 35-40g of barbary wolfberry fruit. The clinical application effective rate of the medicament can be up to 98 percent in maximum, has the advantages of simple medicament composition, appropriate compatibility, low medicinal odor, low price, definite curative effect and the like, and is easily accepted by patients.