The invention relates to a catalpol-containing medicine composition for reducing blood glucose and a preparation method and application thereof. After the catalpol is singly used, or the catalpol is compounded with other active components, such as one or multiple of sulfonylurea, metformin, alpha-glycosidase inhibitors, insulin sensitization agents, glenn urea medicines or traditional Chinese medicine compositions, the excellent effect of reducing blood glucose, triglyceride, cholesterol and glycated hemoglobin in hyperglycemia mice or rats is realized; the catalpol-containing medicine composition can be widely applied to prevent and treat the diabetes, especially type 2 diabetes.