In this paper, in order to avoid aggregate of nanodiamonds and reduce the damage problem caused by the hard abrasives during polishing, a kind of ultra-fine nanodiamond abrasive polishing pad was fabricated by means of sol-gel technology. The polishing pad was then used to polish silicon wafer on a nano-polishing machine. The surface morphologies and roughness were measured by both optical microscope and atomic force microscope (AFM). It is found that it was easy to machine the silicon wafer to mirror surface after polishing with the nanodiamond pad. And the surface roughness of the silicon wafer was reduced to 0.402 nm.