The invention relates to a drug composition for curing hereditary ataxia. The drug composition is made of rehmannia glutinosa, rhizoma anemarrhenae, atractylis ovata, achyranthes, Clematis chinensis, root-bark of tree peony, radix codonopsitis, eucommia bark, common dodder, sealwort, colla corii asini, oyster, salvia miltiorrhiza, milk veteh, caulis spatholobi and/or a medically acceptable carrier. The invention also relates to a method for preparing the drug composition. The drug composition has the functions for tonifying the kidney and spleen, replenishing essence and brain, nourishing liver and calming wind, strengthening tendons and bones, etc., and is used for curing the symptoms of gait instability, swaying walking, nystagmus and asophia, etc. caused by the hereditary ataxia.