Abstract: Some ethers, of bis(dihydroqinghaosu) Ⅲ and bis(dihydrodeoxyqinghaosu) Ⅳ were prepared in order to study the structure-activity relationships and to search for new antimalarials. Compounds Ⅲ were sythesized by condensation of glycol with two moles of dihydroqinghaosu using boron trifluoride etherate as catalyst. Compounds Ⅳ were prepared from ethers of bis (dihydroqinghaosu) by reduction with zinc and acetic acid.The bis-ethers were evaluated against chloroquine-resistant strain of plasmodium berghei in mice. Compounds Ⅲ were less potent than methyl-dihydroqinghaosu (Ⅰ) and compounds Ⅳ were inactive.