A novel polyphenolic compound, named Oxovitisin, with unique lactone pyranone ring and non-oxonium structures was prepared. In this paper, Oxovitisin A was synthesized with two-step reactions in micro-oxygenation system using carboxypyranoanthocyanins formed from pyruvic acid and anthocyanins. The fraction of Oxovitisin A was isolated by a combination of several chromatographic techniques and identified with HPLC-DAD-EI-MS/MS. The results showed that the purity of Oxovitisin A could reach more than 99% after purification. The study investigated the florescence spectra of Oxovitisin A, the effect of different pH value on UV feature and color parameters. The antioxidant activities of Oxovitisin A were evaluated by using a BPCL Ultra-weak luminescence analyzer in vitro, which were compared with that of Vitisin A, Mv-3-gluc and Vitamin C. The results revealed that Oxovitisin A had an obvious fluorescence peaks under the excitation wavelength of 440 nm, but no intensity of florescence was detected on Vitisin A and Mv-3-gluc. Analysis with UV spectroscopy and color parameter variations method indicated that Oxovitisin A had a higher structural and color stability. All four compounds (Oxovitisin A, Vitisin A, Mv-3-gluc, Vitamin C) showed strong antioxidant activity in scavenging O-2 (IC50 of 714, 307, 19, 28 μg·mL-1, respectively), ·OH (168, 3524, 2854, 8441 μg·mL-1, respectively) and H2O2 (1311, 0409 8, 0288, 3265 μg·mL-1, respectively). However, Oxovitisin A showed the highest antioxidant ability in scavenging free radical compared with Vitisin A, Mv-3-gluc and Vitamin C.