Anion-exchange groups were introduced into an existing microfiltration membrane by radiation-induced grafting polymerization and subsequent chemical modification. Glycidyl methacrylate(GMA) was grafted onto the porous polyethylene hollow-fiber membrane. The epoxy group produced in the GMA-grafted hollow fiber was converted into anion-exchange groups by reaction with diethylamine (DEA) and Triethylamine(TEA). Subsequently, the remaining epoxy groups were converted into ethanolamio(EA) groups. When measurements of anion-exchange capacity of the DEA and TEA-fibers were compared with the DEA-EA and TEA-EA fibers, higher anion-exchange capacity were observed.