The invention relates to a medicinal composition for disintoxicating and protecting liver and a preparation method thereof and belongs to the technical field of production of Chinese medicinal preparations. The medicinal decoction for disintoxicating and protecting liver comprises the following edible and pharmaceutical raw materials: hovenia dulcis thunb, vine root, plantain herb and chrysanthemum. The medicinal composition can decompose and convent ethanol and prevents the ethanol from damaging bodies, has the effects of clearing away heat and toxic materials, clearing damp and promoting diuresis, reducing heat and promoting the production of body fluid, protecting liver and improving eyesight, and regulating spleen and stomach, makes drunk people healthy and is a qualified wine partner. The raw materials of the medicinal composition are sweet and delicious, have good effect, are simple and economic and are easy to purchase.