In this paper, an electrochemical copper ion (Cu2+) sensor was constructed based on a glass carbon electrode (GCE) modified with SnS nanosheets supported on graphene (Gr-SnS). The electrochemical behaviors towards Cu2+ were investigated by cyclic voltammetry and linear sweep voltammetry in 1.0 M acidity KCl solution with the pH at 4.5. After optimizing the proportion of SnS to Gr, the best proportion is 2:1. The electrochemical result shows that Gr-SnS nanocomposite modified electrode exhibits good electrochemical performance towards Cu2+ and the reduction peak current was proportional to the Cu2+ concentration in the range from 1.5 to 36.0 mu M with a detection limit of 0.02 mu M (S/N = 3). Besides, the Cu2+ sensor showed a good anti interference performance, high stability and excellent regeneration capability. (C) 2016 Elsevier B.V. All rights reserved.