Hydrophilic polyacrylonitrile (PAN) ultrafiltration membranes are obtained by hydrolysis reaction in 2M NaOH. Hydrophilic modification improves antifouling property of the studied PAN ultrafiltration membranes in separating Salvia Miltiorrhiza decoction: the large steady permeate flux and the short t(ss) are achieved. The content and ratio of danshensu and protocatechuic aldehyde in the permeates are different when PAN membranes with different hydrophilicities are employed for filtration. Its effect on Chinese herbs performance should be further studied. (C) 2007 Elsevier B.V. All rights reserved.