Abstract: Eight coumarins isolated from the alcohol extract of the Chinese drug"Duhuo" , the root of Angelica pubescents Maxim. f. biserrata Shan et Yuan (Umbelliferae) were elucidated to be columbianetin (Ⅰ), columbianetin acetate (Ⅱ), columbiadin (Ⅲ), osthol (Ⅳ), isoimperatorin (Ⅴ), bergapten (Ⅵ), xanthotoxin (Ⅶ), and columbianetin-β-D-glucopyranoside (Ⅷ), by chemical and spectral analysis, compound Ⅷ was isolated from plant for the first time.All these coumarins were tested on platelet aggregation induced by 2μm ADP. Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅷ showed strong inhibiting activity against platelet aggregation.