The silica particles were prepared by using silicon tetrachloride (a main byproduct of polycrystalline silicon production) and sodium silicate as silica precursor, low concentration of nonionic surfactant polyethylene glycol and absolute alcohol as additives. The prepared silica has been characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy and laser particle size analyzer. The results showed that the silica with average size of 150nm could be obtained under optimal conditions, the silica particles could be evenly dispersed because of adding PEG into the reaction solution and the particle size of silica increased with the increase of the concentration of sodium silicate. Therefore it is important to control the concentration of sodium silicate.