The invention specifically relates to application of Spartina alterniflora and Kosteletzkya virginica root tubers to preparation of functional cordial, belonging to the technical field of plant-originated cordial products. According to the invention, the overground part of the original herb of Spartina alterniflora or the extract of Spartina alterniflora, and the Kosteletzkya virginica root tubersor the extract thereof are added into liquor according to a certain ratio to prepare cordial. Study results of the invention prove that the Spartina alterniflora-Kosteletzkya virginica cordial has abright yellow color and pleasant flavor and is capable of resisting gout, helping sleeping, dispelling the effect of alcohol, etc.