Highly ordered diamond/Au nanocomposite structures were fabricated by preparing a honeycomb structured diamond film and subsequent Au deposition into holes by vacuum deposition. The cross-sectional SEM image of the composite film showed Au nanodots at the bottom of the holes. The optical absorption spectrum of the composite film showed a characteristic absorption due to the surface plasmon resonance at the wavelength of similar to 520 nm, indicating the possible application of honeycomb diamond in optoelectronics.