Antioxidative activity of browning product(BP) fractionated from fermented soybean sauce(SS) was studied during the oxidation process of linoleic acid mixture system. SSBP was a powder type product prepared from fermented soybean sauce by the fractionation through the Sephadex G-10 column and freeze drying of collected fraction. The aqueous model systems were used for the evaluation of antioxidative activity of SSBP during the oxidative reaction at $50^{circ}C$ by the determination of peroxider and conjugated dienoic acid compounds. The linoleic acid mixture for the aqueous model systems was consisted of linoleic acid(64.6%), oleic acid(27.4%), and other acids in ethanolic phosphate buffer solution(pH 7.0). SSBP had a considerable antioxidative activity with the inhibition of formation of peroxides and conjugated dienoic acids during the autoxidation of linoleic acid mixtures in aqueous model systems. Antioxidative activity of SSBP was relatively higher than SS, however, lower than ${alpha}-tocopherol$ and butylated hydroxyanisol. The antioxidative effect of SSBP was increased by the its concentrations from 0.05% to 0.5% in the oxidation reactions of aqueous model systems. Therefore, SSBP was considered as one of the potential natural antioxidants for the use of food products.