Abstract: A series of diesters and monoesters of dihydroqinghaosu was prepared and evaluated for their antimalarial activities. These compounds were synthesized by acylation, in some cases, 4-(N, N-dimethylamino)-pyridine (DMAP) was used as acylating catalyst. Most of these compounds were more active than qinghaosu against chloroquineresistant strain of plasmodium berghei in mice. Compound 3 was found to be 9 times as active as qinghaosu. Besides, it seems that the antimalarial activities of diesters were independent of the ester chain lengths.