In the work, we demonstrated the possibility of directly using the existing KMnO4 as Mn precursor and graphite as the carbon precursor in Hummers method to decorate MnO2 nanomaterials over graphene oxide (GO). Nanorod-like alpha-MnO2 in the form of single crystal were found closely decorated over GO. The MnO2 content could be easily adjusted from 45% to 18% by decrease the amount of KMnO4 from 15.0 g to 7.5 g. Compared with the reported work, the developed simplified Hummers method in this work could better utilize KMnO4 by cutting exceed 50% of KMnO4 amount, cut the reagents especially some hazardous reagents from 6-8 items to 3 items, cut 1/3 of the preparation time, avoid high temperature reaction. All those advantages make the simplified Hummers method green, low cost, eco-friendly, time and energy saving, which are beneficial to the industrialization of the MnO2/GO composite. The MnO2/GO composite showed good performance in the degradation of methylene blue with the assistance of H2O2. (C) 2018 Elsevier Ltd. All rights reserved.