The invention discloses a plant source preservative and a preparation method and application thereof. The plant source preservative has a main component of an extract of eupatorium adenophorum leaf, can be used for refreshing fruits, has inhibiting effect on various fruit germs, and particularly has obvious effect of refreshing lichees, longans and bananas. The plant source preservative is a purely natural plant extract, has the advantages of high efficiency, no toxin, environmental friendliness, difficult generation of germ resistance and the like, and can be used as an ideal preservative for refreshing fruits, prolonging the shelf life and preventing postharvest diseases.