Steady alkalescence monodispersed silicasol were obtained from sodium metasilicate by using chemical precipitation. The process employed low Zeta electric potential controlled growth to achieve big grain diameter 130nm. In this work, the best conditions of grain diameter growth were optimized, which included pH, reaction temperature, digestion time, and so on. The performances of the product have been studied by XRD, IR, Nano Particle Analyzer, ζ electric potential and SEM. Sphericity silica nanoparticles with good stability and high dispersion were obtained, which attained the standard of manufacturing production.