The invention provides hypoglycemic tea and a preparation method thereof, and belongs to the technical field of tea and production method thereof. The hypoglycemic tea is prepared from the following raw materials in parts by weight: 5-10 parts of ginseng, 10-15 parts of cortex mori radicis, 8-10 parts of eucommia ulmoides, 10-16 parts of cortex lycii radicis, 20-25 parts of green tea and 20-25 parts of rock candy. The preparation method comprises the following steps: firstly, weighing the following raw materials in parts by weight: 5-10 parts of ginseng, 10-15 parts of cortex mori radicis, 8-10 parts of eucommia ulmoides, 10-16 parts of cortex lycii radicis, 20-25 parts of green tea and 20-25 parts of rock candy; then, uniformly stirring ginseng, cortex mori radicis, eucommia ulmoides, cortex lycii radicis and green tea in a dust-free and sterile environment, grinding to obtain powder of 40-60 meshes, and screening to filter out residues; and grinding rock candy, uniformly mixing with the powder, filling into bags and sealing. The hypoglycemic tea closely combines the therapeutic effect of medicinal materials and health-protecting effect of tea, can be used for lowering blood glucose, does not have toxic or side effect on human bodies, and cannot hurt human bodies.