Background <p>In the field of microscale ultra-precision machining, the radial vibration of aerostatic spindles is a key factor affecting machining accuracy, and the role of process damping in regulating this vibration remains to be systematically clarified.</p> Purpose <p>This research focuses on exploring how process damping influences the radial vibration of aerostatic spindles under such cutting conditions, establishing a corresponding dynamic model, and verifying the model’s accuracy.</p> Methods <p>Methodologically, an interference volume identification model is built based on the tool-workpiece indentation effect to calculate process damping, the LFR model is used to modify the unsteady Reynolds equation and integrate process damping into the aerostatic spindle dynamics model, followed by simulation of the spindle’s dynamic characteristics at 1000–4000 r/min conducted via MATLAB’s ODE45 function, and experimental verification is performed using a bidirectional dynamic measurement system to collect radial vibration data.</p> Results <p>The results show that process damping significantly suppresses radial translational vibrations at low speeds, with the suppression effect weakening as speed increases; it has little impact on radial angular displacements.</p> Conclusion <p>It is concluded that process damping effectively suppresses the low-speed radial translational vibration of the aerostatic spindle, and the established model is consistent with actual machining, providing a basis for spindle vibration control in ultra-precision machining.</p>