In this paper, an experimental study was carried out to fabricate a new kind of ultra-fine diamond abrasive tools by means of sol-gel. The physical properties of the new diamond abrasive tools were evaluated in terms of the bulk density and hardness. The ultra-fine diamond tools were then used to polish granite on a vertical spindle grinding machine. SEM and optical microscope were applied to observe the surface morphologies of the diamond tools and granite. No obvious gathering of ultra-fine diamond grains were found in the new diamond abrasive tools, which exhibited a good wear-resistant ability in polishing. The granite surfaces polished by the new diamond tools were found to be basically smooth except few cracks originally existing in the granite.