Traditional Chinese medicine for treating diabetes mellitus and preparation method of traditional Chinese medicine

The invention discloses a traditional Chinese medicine for treating diabetes mellitus. The traditional Chinese medicine is composed of the following components by weight: 0-20g of polished round-grained rice, 0-15g of dendrobium, 5-25g of medlar leaves, 0-15g of schisandra chinensis, 0-10g of radix rehmanniae, 5-25g of Chinese yams, 0-10g of radix aucklandiae and 0-20g of ligusticum wallichii. The traditional Chinese medicine is prepared through the following steps of placing all the components into an earthenware pot; adding water to soak the components for 2-4 hours; heating the earthenware pot on the fire; after boiling on a big fire, decocting on a small fire for 30-35 minutes; then, filtering a decoction in a vessel through gauze so as to be taken, wherein each part of medicine can be decocted twice. The traditional Chinese medicine has the advantages of good treating effect, no side effects and the like.