The MeOH extract from root of Pulsatilla koreana was showed antimicrobial activities against bacteria and yeast. The antimicrobial active substances of MeOH extract were successfully purified with solvent fractionation, silica gel adsorption column chromatography and Sephadex LH-20 column chromatography. The purilfied two active substances were isolated by HPLC and identified as 4-hydroxy-3-methoxycinnamic acid and 3,4-dihydroxycinnamic acid by MS, ¹H-NMR and ^(13)C-NMR.