Angelica polymorpha Maxim. is a plant of the Angelica genus (Umbelliferae). The root and stem of this plant is a folk medicine known to have the actions of relieving rheumatism and cold and subsiding swelling and pains. To investigate the chemical constituents in the root of A. polymorpha Maxim., seven compounds were isolated from an 80% ethanol extract by column chromatography. Their structures were elucidated according to the spectroscopic analysis. Compound 1 is a new sesquiterpene, named as bisabolactone. Its absolute configuration was determined by 1D NOESY and CD analysis. The others were identified as 5-hydroxymethylfurfural (2), hycandinic acid ester 1 (3), ferulic acid (4), isooxypeucedanin (5), noreugenin (6) and cimifugin (7). Compound 2 and 3 were isolated from this genus for the first time and compound 4 was isolated from this plant for the first time.