Abstract: AimIn order to look for new bioactive compounds, investigation on the chemical constituents, especially on the typical polyacetylenes from the rhizomes of Cirsium japonicum DC. was carried out. Methods Chromatographic techniques including silica column chromatography and preparative silica thin-layer chromatography were used to separate and purify the constituents. Their structures were elucidated by physico-chemical properties and spectral analyses including UV, IR, ¹HNMR, ¹³CNMR, HMQC, HMBC and HREIMS. ResultsTwelve compounds were isolated from the rhizomes of Cirsium japonicum DC., and their structures were identified as cis-8, 9-epoxy-heptadeca-1-ene-11, 13-diyne-10-ol (1), ciryneol A (2), 8,9,10-triacetoxy-heptadeca-1-ene-11,13-diyne (3), ciryneone F (4), cireneol G (5), ciryneol H (6), ciryneol C (7), P-coumaric acid (8), syringin (9),linarin (10), β-sitosterol (11) and daucosterol (12). Conclusion Compounds 4, 5 and 6 are new compounds, compound 3 is a new natural product and compound 8 was isolated from this plant for the first time.