The invention discloses a Chinese medicinal composition for preventing and treating chicken diseases and a preparation method thereof. A medicament is prepared from fineleaf schizonepeta herb, divaricate saposhnikovia root, Chinese thorowax root, large-head atractylodes rhizome, honeysuckle flower, weeping forsythia, heartleaf houttuynia herb, isatis root, Chinese pulsatilla root, virgate wormwood herb, sweet wormwood herb, rhubarb, lightyellow sophora root, hairyvein agrimonia herb and bud and liquoric root in a certain weight ratio. The medicament has the effects of clearing away heat and toxic materials, strengthening body resistance, eliminating evil, nourishing yin, cooling the blood, discharging fire, eliminating dampness, killing parasites, resisting bacteria, diminishing inflammation, relieving dysentery with astringent, promoting qi circulation, relieving pain, warming the middle warmer, harmonizing stomach, warming kidney, enhancing yang, promoting digestion and opening spleen, can be used for effectively preventing and treating respiratory diseases, digestive tract diseases and protozoal diseases of chicken, and has a good effect. Raw materials for preparing the medicament belong to pure natural Chinese medicinal materials, so that the medicament has a small side effect, and chicken quality is improved. The medicament has the advantages of sufficient resources, simple preparation method and low cost.