In this paper, the Cu2+ ion-imprinted polymer (Cu2+-IIP) was prepared in the homogeneous phase by the ion-imprinted technology. Polyethyleneimine was used as the basic bone which was rich in amino-functionalized groups to coordinate with template Cu2+ and the 1,2-bibromoethane was used as a crosslinker. The chemical structure and surface morphology of the imprinted polymer were characterized by Fourier transform infrared spectroscopy (FTIR) and the scanning electron microscopy (SEM). Batch adsorption studies were performed to evaluate the adsorption capacity, the adsorption isotherm and the adsorption selectivity of Cu2+-IIP. The maximum adsorption capacity of Cu2+-IIP was 83.3 mg/g, significantly more than most of the reported adsorbents and also about 2.4 times that of non-imprinted polymer (Non-IIP) in this work. In addition, Cu2+-IIP performed good adsorption selectivity towards Cu2+ with the interference of Ni2+, Zn2+, or Pb2+. These results indicated that Cu2+-IIP is a promising absorbent for the real wastewater treatment.