The branches and leaves of Croton yunnanensis were dried and extracted with methanol.The chemical compo-nents were separated and purified by silica gel column chromatography,MCI column chromatography,Sephadex LH-20 gel column chromatography and HPLC.These compounds were identified as(-)-ent-6α-methoxyeudesm-4(15)-en-1β-ol(1),oplodiol(2),(7R*)-opposit-4(15)-ene-1β,7-diol(3),aphanamol I(4)and orientalol C(5).Compounds 1-4 were isolated from this plant for the first time.