The invention discloses a drug for treating kidney calculus, and a preparation method thereof. The drug is composed by a combination of 25 traditional Chinese medicines comprising unprocessed radix aconiti lateralis, rhizoma zingiberis, rhizoma cibotii, as arum, semen coicis, cassia twig, cortex cinnamomi, licorice root, poria cocos, eucommia, jujube kernel, radix dipsaci, white peony root, bighead atractylodes rhizome, Chinese yam, christina loosestrife herb, talcum powder, rhizoma cyperi, bryozoatum, rhizoma curcumae, rhizoma sparganii, Fried chicken's gizzard-membrane, epimedium, radix morindae officinalis and radix aconite lateralis preparata. The above traditional Chinese medicines are pretreated by crushing or water decoction extraction and then made into granules or pills by adding an excipient. The drug has the functions of clearing heat and draining dampness, promoting the circulation of qi to remove blood stasis and treating stranguria and removing calculus, is suitable for treatment of the kidney calculus, can make the calculus reduced in size and expelled from the body, and can prevent calculus infections, alleviate pains of a patient, protect the function of the kidney and prevent recurrence effectively.