The invention provides a liquid antioxidant composition and application thereof. The liquid antioxidant composition is prepared from the components in parts by weight: 30 to 65 parts of dimethyldipropionate dipropionate, 35 to 60 parts of at least one of hindered phenolic antioxidant, and 0 to 15 parts of at least one of phosphite ester antioxidants. The liquid antioxidant can be widely applied toan oil product, so that the oxidation stability of the oil product can be greatly improved. More importantly, the liquid antioxidant composition is a liquid so as to have great convenience in transporting and feeding, can ensure the continuous production of the oil product, has the characteristic of capability of quickly dispersing in the oil product at the same time, and has an incomparable superior characteristic compared with other solid antioxidants.