The invention discloses a plant antioxidant functional feed additive, which is prepared from the following raw materials in parts by weight: 0 to 10 parts of 2,6-di-tert-butyl-p-cresol, 1 to 10 parts of ethoxyquin, 1 to 5 parts of methionine hydroxy analog, 1 to 5 parts of talc powder, 1 to 10 parts of citric acid monohydrate, 1 to 80 parts of ampelopsis, and 5 to 20 parts of medical stones. The additive has the advantages that: the traditional natural plant ampelopsis is applied to livestock production, the ampelopsis containing natural plant anti-oxidation mould inhibitor dihydromyricetin has good effects of removing free radicals and resisting lipid peroxidation, and the problem of oxidizing grease in the feed rich in Cu<2+>, Fe<2+> and other metal ions can be solved; and therefore, the additive is a high-efficiency green functional anti-mould anti-oxidation additive product. The additive can be used as an excellent substitute product for chemically synthesized anti-mould anti-oxidation products, so that a new opportunity is brought to the development of feed industry, and establishment of a healthy culture production mode is facilitated.