Objective: Cimicifuga dahurica (Ranunculaceae) has many bioactivities. Although there have been intensive studies for saponin constituents at present, only a few studies have focused on for chemical constituents of phenolic acid. To define the phenolic acid constituents,C. dahurica was separated, and the structures of the compounds were identified,in the expectation of providing a basis for its further development,utilization and quality control. Method: A total of 16 kg rhizome of C. dahurica was extracted with 70%ethanol for three times by heating reflux. These 3 extracts were decompressed and concentrated,and then dissolved in water. Then the solvent was successively extracted with petroleum ether,ethyl acetate(EtOAc) and n-butanol(BuOH). The components of EtOAc and water extract were isolated and purified by macroporous,silica gel,ODS,Sephadex LH-20 column chromatography,preparative HPLC and recrystallization,and the structures were identified by nuclear magnetic resonance(NMR) and physicochemical analysis etc. Result: Fifteen compounds were isolated from the ethyl acetate and water fractions,and identified as cimicifugic G (1),2-caffeoyl piscidic acid (2),cimicifugic A (3),cimicifugic B (4),caffeic acid 3-O-β-D-glucopyranoside (5),cimicifugic E (6),cimicifugic F (7),trans-ferulic acid 4-O-β-D-glucopyranoside (8),carboxymethyl isoferulate (9),3,4-dimethoxycinnamic acid (10),ethyl ferulate (11),caffeic ester glucoside (12),shomaside A (13),isoferulic acid (14),caffeic acid (15). Conclusion: Compounds 1-7,9-10,13 were isolated from the plant for the first time.