Two galvanic reduction steps and one galvanic displacement reaction are developed as a new and simple method for modification of glassy carbon electrode (GCE). The GCE was modified by a three-dimensional Pd-Cd nanostructure that decorated on reduced graphene oxide. For the preparation of the modified electrode, firstly deposited graphene oxide layer and cadmium (II) chloride on the GCE are reduced to graphene (rGO) and metallic cadmium, respectively by new strategy using Zn/HCl system. Then, three-dimensional palladium nanonetwork is created on the electrode by the galvanic displacement reaction. As-prepared catalyst has been characterized by the field emission scanning electron microscopy (FESEM), the energy-dispersive X-ray spectra (EDX), and the electrochemical measurements. The obtained peak current density of ethanol oxidation on the Pd-Cd/rGO is 179 mAcm(-2), which is 4.47 times higher than that commercial Pd/C catalyst (40 mAcm(-2)).