The plasma polishing and etching system independently developed by the laboratory was used to prepare sapphire self-organized nanostructures. The formation mechanism of self-organized nanostructures by Ar⁺ ion beam sputtering assisted with stainless steel at different incident energy was studied. The roughness， longitudinal height of nanostructure and surface morphology of the etched sapphire sample were respectively measured by Taylor Surf CCI2000 non-contact surface measuring instrument and atomic force microscope. With the ion beam incident angle of 65°， the beam current density of 487 μA/cm²， the etching time of 60 min， and the ion beam incident energy of 1 000 eV， well-ordered stripe-like nanostructures with a longitudinal height of 11.1 nm appear on the surface of the sapphire sample. As the incident energy increases， island-like nanostructures gradually appear on the surface of the substrate. When the incident energy is 1 200 eV， island-like structures and ripple generate on the substrate， with a longtidudinal height of 13.6 nm. With an increase of the incident energy， the density of island-like structures enhances. When the incident energy is 1 400 eV， the longitudinal height of island-like nanostructures is 18.8 nm.When the incident energy is 1 600 eV， the surface of the sapphire sample appears a relatively ordered island-like structure with a longitudinal height of 20.1 nm. During the ion beam sputtering process， with an increase of the incident energy， metal impurities break the balance between the surface growth mechanism and the surface smoothing mechanism， which form island-like nanostructures， these structures promote the growth of nanostructures and change the orderliness of nanostructures.