Three new sesquiterpenoids, named yunnanolides J-K and yunnanol A (1-3), together with ten known sesquiterpenoids (4-13), have been isolated from the dried whole plants of Ainsliaea yunnanensis Franch. The chemical structures of compounds 1-3 were elucidated by NMR and HRESIMS analysis. All the compounds were tested for in vitro cytotoxicity against three human tumor cell lines (95D, MDA-MB-231, and HepG2). Compound 13 showed moderate cytotoxicity against human cancer cell lines MDA-MB-231 (IC50 = 18.2 mu M) and HepG2 (IC50 = 12.2 mu M), respectively.