An ion imprinting polymer (IIP) electrochemical sensors based on chitosan-graphene oxide composites polymer modified glassy carbon electrode (CS/GO-IIP) was developed for the highly sensitive and selective detection of Cu (II) by the dip coating method. The Cu (II) ion-imprinted polymers were synthesized by chemically cross-linking with epichlorohydrin after the CS/GO/Cu (II) composite dropped on the glassy carbon electrode surface. The introduction of GO can improve the electrical conductivity of the electrode and amplify the electrochemical signal. The sensor was characterized by FT-IR, EDS, SEM, AFM, Raman spectroscopy and electrochemical measurements. Under the optimized conditions, a linear dependence was observed from 0.5 to 100 mu mol/L with a detection limit of 0.15 mu mol/L. The detection of Cu (II) was hardly interfered by the traditional metal cations. The CS/GO-IIP sensor showed excellent reproducibility via repetitive differential pulse anodic stripping voltammetry and the RSD was 3.3%. More importantly, the performance of CS/GO-IIP sensor was verified in tap and river water samples and has an acceptable recovery rates. (C) 2019 Elsevier Ltd. All rights reserved.