Abstract: In searching for a safe,radically curative antimalarial agent and a causal prophylactic, a series of 5-substituted phenoxy-6-methoxy-8-(1-ethyl-4-aminobutyl) amino quinolines (Ⅲ) was prepared by condensation of 5-substituted phenoxy-6-methoxy-8-aminoquinoline with N-(4-bromohexyl)phthalimide and subsequent hydrazinolysis.The compounds were tested for suppressive antimalarial activity against P. berghei in mice and for causal prophylactive activity against P. yoelii in mice. Most of them were less active then primaquin at 20mg/kg.