Two new sesquiterpene lactones 3R, 8R-dihydroxygermacr-4(15),9(10)-dien-6S,7S,11RH,12,6-olide (1) and 1R, 8S-dihydroxy-11R,13-dihydrobalchanin(2), together with two known compounds 11-epiartapshin (3) and 3'-hydroxygenkwanin (4), were isolated from Artemisia sieberi. Their structures were elucidated