The present invention discloses a method for surface-treating a mirror-finish stainless steel workpiece, which comprises steps: dividing the surface of a mirror-finish stainless steel workpiece into different grinding areas according to the depths of the scratches; selecting sand papers respectively having appropriate grit sizes for the grinding areas, and grinding the grinding areas to remove all the scratches; sequentially using three combinations of polishing agents and grinding materials to undertake polishing; and using an abrasive paste and a fourth grinding material to perform mirror-finishing.