The invention provides a method for preparing a natural antioxidative food additive. The method is characterized by comprising the following steps that: wine Hanseniaspora uvarum, monascus purpureus, Acetobacter pasteurianus and Lactobacillus bulgaricus are cultured on a respective culture medium by an eggplant shaped flask, and are inoculated into LB culture fluid to be fermented and concentrated to obtain the natural antioxidative food additive. The natural antioxidative food additive does not have organic solvent residual, has complete and stable antioxidation capability.