A three-dimensional palladium nanonetwork decorated on reduced graphene oxide (rGO) is synthesized by a simple and rapid method. In this method, graphene oxide (GO) is reduced on a glassy carbon electrode by Zn/HCl system. After reduction of GO to rGO, three dimensional Pd nanonetwork is fabricated on rGO by reduction of deposited PdCl2 using Zn/HCl system. The morphology and chemical composition of as-prepared 3-D Pd/rGO catalyst are characterized by scanning electron microscopy and energy dispersive spectroscopy, respectively. We revealed that the as-synthesized 3-D Pd nanonetwork shows excellent electrocatalytic activity and durability toward ethanol oxidation due to the formation of the 3-D nanonetwork and porous structure. The specific activity of 3-D Pd/rGO toward ethanol oxidation is 12.3 times higher than commercial Pd/C. Durability and tolerance to carbonaceous intermediates accumulation of the as-prepared catalyst are also greatly improved.