A novel Cu2+-imprinted fiber (IIF) was prepared by grafting acrylic acid (AA) onto the surface of a polypropylene (PP) fiber and subsequently modified with polyethylenimine (PEI). An examination by infrared spectroscopy and scanning electron microscopy confirmed that the ion-imprinted polymer was successfully introduced onto the surface of a PP fiber. The modification of PP fibers with AA was beneficial to the grafting of PEI onto the fibers. The highest grafting degree of PEI could reach 120 wt % under optimal grafting conditions. This IIF showed excellent tensile and chemical stability in acid solution, which qualified the IIF for practical applications. Besides having a high adsorption capacity for Cu2+ (120 mg/g), the IIF adsorbent showed a high selectivity for Cu2+ as compared with that of the non-ion-imprinted fiber (NIF). The dynamic adsorption results indicated that IIF can thoroughly remove Cu2+ from the solution in a relatively short contact time. The effective treatment volume was about 910 bed volumes. The selectivity coefficient of IIF for Cu2+ with respect to Zn2+ could reach 76.4. IIF also has good regeneration performance and could maintain almost the same adsorption capacity for copper ions after 10 adsorption-desorption cycles.