Anodic aluminum oxide (AAO) is a self-organized nanostructured material that contains high-density, uniform cylindrical pores that are aligned perpendicularly to the surface of the materials. Therefore, AAO nanostructures are very useful templates for applications such as electrochemical detection of metal ions and fabrication of nanowires or nanotubes. We fabricated an AAO template thorough two-step anodizing as an electrochemical sensing electrode. Gold nanowire (GNW) was prepared via in-situ electrochemical deposition on the AAO template. Then, the GNW/AAO electrode was functionalized with 1,6-hexadecanethiol. In the electrochemical analysis, the electron signals of the GNW/AAO changed by combining mercury ion and the thiol group on the electrode. The amperometric response was determined in the presence of the mercury ions. Consequently, a proof-of-concept test showed that the GNW/AAO electrode is a possible tool that can act as a heavy metal ion sensor.