Self-organized nanostripe pattes with a wavelength of l00nm and an amplitude of 4 - 5nm were formed Seon the surface of high-purity aluminium by electropolishing. The thermal stability of the nanostripe pattes was investigated experimentally by using a needle-sensor atomic force microscope in an ultra-high vacuum after annealing the sample in a high vacuum. We found that the originally highly ordered nanostripe structures transformed into many domains separated by various boundaries, and different nanostripe pattes formed, the belt-like boundaries especially formed "cross" pattes on the surface. We also found that the vacuum annealing had the tendency to efface the nanostripe structures.