<p>The polished surface quality of coatings has been the key aspects that directly determine the optical performance of telescope, especially for the high-resolution ones, e.g., space telescope, while giant electrorheological polishing is one of the most promising techniques to achieve superior surface finish of components. A multiscale methodology, integrating molecular dynamics simulations with first-principles calculations, is adopted in this investigation to reveal the material removal mechanisms of different micro-polishing parameters. In surface–microscale, molecular dynamics simulations were employed to model material removal behavior during polishing, where abrasive particles slide across the workpiece surface, and the influence patterns of multiple polishing parameters were systematically investigated. It was found that the indicators of stress, strain, and atomic stacking exhibit a core characteristic of “depth-dominated, velocity-regulated” response to processing parameters. At subsurface–mesoscale, the characterization of subsurface structures under different parameters revealed patterns in lattice evolution, dislocation dynamics, and surface defect characteristics during polishing. As polishing depth increases, the internal dislocation density of the material progressively rises, during which a distinctive three-dimensional tetrahedral stair-rod dislocation ring structure emerges. At atomic–electronic scale, a combination of first-principles calculations and molecular dynamics simulations was employed to further evaluate the mechanical properties of Ni-coatings. First-principles calculations and electron density analysis together elucidate the anisotropic elasticity of Ni-coatings, revealing the orientation-dependence of the elastic modulus and confirming the {111} plane as the shear weak plane. This study provides mechanistic support for optimizing Ni-coating polishing parameters and enhancing the surface quality of optical components.</p> Graphical abstract <p></p>