Abstract: Antioxidant feed additives can eliminate free radicals in the body and enhance antioxidant capacity, and characterized by green safety, non-toxicity, environmental friendly, and no drug residues, it has been widely applied in animal production. The article based on research progress regarding the physicochemical properties, antioxidant mechanisms, and applications of seven major categories of feed antioxidant additives. Plant extracts directly eliminated free radicals through active components such as flavonoids and polyphenols. Probiotics improved endogenous antioxidant enzyme activity by regulating intestinal flora. Vitamins protected cell membranes by blocking oxidative chain reactions. Trace elements maintained oxidation-reduction balance as cofactors of antioxidant enzymes. Enzymatic antioxidants include SOD, which could be preparation of antioxidant peptides and exerts antioxidant effects in animals. Organic compounds exert antioxidant effected through multiple pathways. Algae and diatom were rich in unique active components such as fucoxanthin, which possessed antioxidant properties. Research on various additives demonstrates that through mechanisms including direct eliminating of reactive oxygen species, enhancing antioxidant enzyme activity, and activating cell-protective signaling pathways such as Nrf2, they effectively alleviate oxidative stress in animals, improve animal product quality and production performance, providing important theoretical basis and data reference for the green and healthy development of animal husbandry.