We report a method to adjust the size of silica nanoparticles from silica sand. In this study, synthesized silica nanoparticles by sol gel process from silica sand were conducted, with previously was controlled the size of silica sand by mechanical milling. Silica sand was milled by High Energy Milling in order to reduce the size into powder form. Effect of milling time shown the content of sodium and silicon is increased in sodium silicate solution obtained from various times of silica sand milling (30, 60 and 90 minutes, respectively) which is reacted with sodium hydroxide 8 M. The result of silica nanoparticles from sol gel process of sodium silicate solution were characterized using atomic absorption spectroscopy, scanning electron microscopy and X-ray diffraction techniques. It was found that the size of silica nanoparticles could be tailored with the change of milling time.