The invention provides a preparation method for licorice root-sweet potato syrup. The licorice root-sweet potato syrup uses green pollution-free selenium-enriched sweet potatoes and wheat as main components and is prepared by using an advanced technology and a unique recipe. The produced licorice root-sweet potato syrup has a dark red color and sweet, delicious and unique taste, presents anti-cancer, anti-virus, antihypertensive, beauty-remaining and other maintenance functions, and is green and natural foodstuff low in cost and simple in production process. Through addition of licorice roots,the licorice root-sweet potato syrup is beneficial for tonifying the spleen, replenishing qi, moistening the lung to arrest cough, relieving pain, mildening medicinal properties, and clearing away heat and toxic matters.