Abstract: The extinction spectra and field distribution of the surface plasmon coupling of metallic nanorod dimmer structures in horizontal and vertical arrangements are calculated by the discrete dipole approximation. It is demonstrated that the peaks of extinction spectra will be red-shifted or blue-shifted due to the different arrangement and gap parameters. The appropriate separation gap has the stronger local electric field distribution for Au nanorod dimmers. The calculation results are expected to have potential applications in nano-scale probing device, nano-sized photocatalyst and biological sensors.