Gold nanostructures were formed when Au nanolayers were deposited on native‐oxide‐covered Si substrates and annealed. To analyze the annealing temperature dependent surface morphology, we calculated the height–height correlation function and the power spectrum density function from the atomic force microscopy image data. When the annealing temperature for 20 nm thick Au layer increased from 500 to 700 °C, the interface width w and the lateral correlation length ξ of the surface increased obviously from 4.8 to 44.0 nm and from 70.5 to 180.9 nm, respectively. On the other hand, the roughness exponent α was a relatively universal parameter (∼0.87). While the morphology of the surfaces was mainly self‐affine, suggesting that the random surface diffusion plays a dominant role in the kinetic roughening process of such an annealed system, the results of the morphological analysis also imply that the self‐affine surface begins to become mounded for higher annealing temperatures.