In this paper, a newly developed ultra-fine abrasive polishing pad by gel technology was adopted to polish silicon wafer on a nano-polishing machine. In order to evaluate the machining performances of the polishing pad, the influences of abrasive sizes, abrasive concentration and polishing parameters (pressure, rotating speed and machining time) on the silicon wafer were investigated respectively. Optical microscope and ZYGO 3D surface analyzer were applied to examine the surface morphologies and surface roughness of the polished silicon wafer respectively. The experimental results showed that the surface roughness of silicon wafer decreased with the decreasing of abrasive grits and the increasing of abrasive concentration and polishing parameters (pressure, rotating speed and polishing time) when polishing silicon wafer with the polishing pad containing Al2O3 abrasive. When abrasive concentration, polishing pressure and polishing time reached certain values, few changes would happen for the silicon wafer.