Abstract: Bridging GaN nanowires (NWs) were prepared by using metalorganic chemical vapor deposition (MOCVD). The bridging GaN NWs were grown over a deep trench on the substrate. Owning to the absence of contact barrier at the electrodes of bridging NWs, the Joule-heating can be generated mainly on the NWs itself rather than on the electrodes. The COMSOL simulation and the resistance measurement all indicated that the bridging NWs were oxidized at a bias voltage of 3V, and the thermal break down occurred at 9V. This work provides a simple method for in situ precise control of NW resistance, which can be further applied to the formation of core/shell NWs with different materials.