Abstract: Ten baicalein derivatives with bronchodilation activity were selectively synthesized using baicalin as a starting material and applying its glycosyl group as a protecting group.Their structures were confirmed by IR，MS and ¹H NMR dataThe preliminary biological assay results showed that the Baicalein derivatives could inhibit contraction of tracheal smooth muscle induced by acetylcholine(Ach)，KCl and histamine(His) in guinea pigThis finding indicates a potential application of Baicalein derivatives in chronic obstructive pulmonary diseases(COPD).