In this paper, N-doped reduced graphene oxide and MnO2 nanocomposite (N-RGO/MnO2) was synthesized via hydrothermal method, which was used to modify the glass carbon electrode (GCE) for electrochemical detection of Hg2+. p-phenylenediamine was used as the nitrogen source and "bridging" molecule between MnO2 and RGO. The electrochemical sensing performance towards Hg2+ was evaluated by square wave anodic stripping voltammetry method. The presence of N-RGO/MnO2 nanocomposite has enhanced the electrochemical performance of the GCE toward Hg2+. The N-RGO/MnO2 nanocomposite modified electrode was found to have a good sensitivity toward Hg2+ and the favorable sensitivity (72.16 mA/mM) and LOD (0.0414 nM) for Hg2+ were achieved under the optimized conditions. Moreover, the modified electrode possessed a good stability and reproducibility. The excellent performance can be attributed to the characteristic nanostructure and N-doping property of the N-RGO/MnO2 nanocomposite. This electrochemical sensing strategy is expected to enrich the application field of electrochemical determination and does good to the issue of environment pollution analysis. (C) 2018 Elsevier Ltd. All rights reserved.