Abstract: To explore the molecular composition and antioxidant activity of flavonoids in oil-tea camellia seed cake, the optimized extraction and purification method was used to purify the flavonoids in the seed cake and the HZ816 macroporous adsorption resin was used for the enrichment and purification, then the silica gel column was used to chromatograph the flavonoid compounds and two flavonoid compounds were obtained, which were designated as compounds Ⅰ and Ⅱ. The two flavonoid compounds were identified by nuclear magnetic resonance, mass spectrometry, infrared and ultraviolet spectroscopy.The results revealed that: the two substances were kaempferol 3-O-2-O-β-D-xylopyranosyl-6-O-α-L-rhamnopyranosyl-β-D-glucopyranoside ( Ⅰ) and kaempferol 3-O-2-O-β-D-galactopyranosyl-6-O-α-L-rhamnopyranosyl-β-D-glucopyranoside ( Ⅱ) . The antioxidant test was carried out on the isolated flavonoid compounds using 1, 1-diphenyl-3-nitrophenylhydrazine radical scavenging ( DPPH method) and pyrogallol autoxidation in vitro.The results showed that the IC₅₀ of DPPH free radicals of the total flavonoids, compound I and compound II was 0.44, 1.88, 2.41 mg/m L respectively, and the IC₅₀ of superoxide anion free radicals was 1.38, 1.13, 1.29 mg/m L respectively.