A Polyphenolic Compound was isolated from ethyl acetate fraction of Panax ginseng. And the chemical structure of its permethyl ether was suggested as 6-[2(3,4-dimethoxyphenyl)ethenyl]-5-(3,4-dimethoxyphenyl)2,8,10-trimethoxybenzo[a] xanthen-9-one by spectroscopic and chemical degradative evidences.