A high-purity compound was extracted by solvent extraction, liquid-liquid separation, silica gel chromatography and high-performance liquid semi-preparative chromatography by using seeds of Camellia semiserrata Chi. as raw materials. The compound was identified as kaempferol-3-O-\[α-L-rhamnopyranosyl-(1-3)- 2,4-di-O-acetyl-α-L-rhamnopyranosyl-(1-6)\]-β-D-glucopyranoside, an acetyl flavonoid glycoside, by physical and chemical properties, mass spectrometry and nuclear magnetic resonance. Two-dimensional nuclear magnetic resonance (2D-NMR) techniques including H-H COSY, HSQC, HMBC and TOCSY were used to affiliate its ¹H and ¹³C NMR chemical shift and explain the structure.