A Chinese medicine in the form of oral liquid for treating diabetes and improving immunity and resistance to virus and infection is prepared from amino acid protein, water and 10 Chinese-medicinal materials including eucommia bark, astragalus root, wolfberry fruit, pueraria root, etc through washing, immersing in alcohol, steaming, filering, baking, immersing in alcohol, filtering, baking, immersing in alcohol, filtering, baking, immersing in warm water, filtering, freeze drying, mixing with amino acid protein and water, and sterilizing.