We used a microwave gyro resonance ion source to study the etching effects on the surfaces of rotating sapphire samples under different Kr +-ion beam parameters. We used the four-factor and three-level orthogonal experiments to analyze the influences of the incident angle, energy, ion flux density, and action time of a Kr +-ion beam on the sapphire surface structures after irradiation. We also studied the relationship between ion beam parameters and sapphire surface roughness and etching rates. The experimental results demonstrate that when an ion beam has an incident angle of 60°, an energy of 600 eV, an ion flux density of 239 μA·cm -2, and action time of 90 min, the sample surface roughness after etching is the greatest and the dot-like structures are formed on the sample surface. In contrast, under the same incident angle, energy, and ion flux density of the ion beam, but a shorter etching time of 30 min, the etching rate reaches its maximum value and the dot-like structures on the surface are dense. Therefore, one can obtain good dot-like nanostructures, optimal roughness and etching rate using the optimal combination of parameters.