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), hydroxylamine(HA) and Triethylamine(TEA). Subsequently, HA membrane adsorption of formaldehyde better then DEA, TEA membrane.