The invention discloses a drug for curing and preventing cardiorenal failure and a preparation method thereof, which is prepared by the following materials by weight percent: 200-300 of prepared rhizome of rehmannia, 150-250 of dioscorea opposita thunb, 150-250 of sweet potato, 150-250 of radix achyranthis bidentatae, 150-250 of eucommia bark, 150-250 of morinda officinalis, 150-250 of polygala root, 150-250 of schisandra chinensis, 150-250 of semen cuscutae, 100-200 of rhizoma acori graminei, 200-300 of medlar, 150-250 of tuckahoe, 150-250 of herba cistanche, 150-250 of fructus broussonetiae, 100-200 of magnolia officinalis, 50-150 of dried orange peel, 30-80 of fructus aurantii, 30-80 of fennel, 30-80 of liquorices, 50-150 of salvia miltiorrhiza and 30-80 of angelica. The drug mainly cures cardiorenal failure, curves diseases and strengths bodies, prolongs lives, and is also helpful to give birth to babies.