The invention discloses yacon tea for clearing liver and detoxifying and a preparation method thereof. The yacon tea consists of the following raw materials by weight: 80-120 parts of yacon, 2-4 parts of gallnut pollen, 5-8 parts of tremella powder, 10-20 parts of emblic leafflower fruit juice, 15-20 parts of bayberry juice, 6-8 parts of Chinese artichoke, 8-10 parts of lily petals, 8-10 parts of Nymphoides peltatum flowers, 10-12 parts of barley powder, 2-4 parts of Kangxian flowers, 1-3 parts of bellflower, 2-3 parts of pseudo-ginseng, 1-2 parts of stellate cladonia fruticose thallus, 2-3 parts of Broussonetia papyrifera, 2-3 parts of hovenia dulcis thunb, and a proper amount of black garlic nutrient solution. The yacon tea for clearing liver and detoxifying combines drink and food as one, is sanitary and convenient, has strong fragrant moist taste, rich and balanced nutrition and the functions of nourishing yin and spleen, protecting liver, strengthening stomach, cooling blood, detoxifying, soothing the nerves, eliminating vexation, promoting digestion and absorption, enhancing liver lipid metabolism, improving liver detoxification function and nourishing the five internal organs; therefore, the yacon tea is beneficial to the human body health.