In this document, the electrolytic in-process dressing ( ELID ) grinding technique is used for ultra-precision processing experimental research on the carbonized cold-rolled steel (HRC60~80).A surface roughness of Ra6~8nm was obtained after ELID precision grinding. The results proved that adopting micro grain size (W1.5~W36) and high hardness cast iron based diamond grinding wheel, increasing the wheel peripheral velocity (18~20m/s) and reducing grinding depth can effectively improve surface quality and bring the surface roughness down. The wheel peripheral velocity, grinding depth as well as grinding fluid are the main factors during ultra-precision grinding.