In order to evaluate the effects of sol-gel transition parameters of TEOS(tetra-ethyl-ortho-silicate)on properties of SiO₂, we studied whole process from sol-gel transition of TEOS by hydrolysis reaction to a sintering step to form SiO₂. Initial hydrolysis parameters of TEOS had an influence on gel shape and transition properties as well as on the bulk density and surface area of the final sintered products of SiO₂. In acid catalyst system, with increasing hydrolysis reaction temperature, fiber drawing zone of sol-gel had become smaller. In closed system no fiber was obtained. Incease in H₂O concentration enhanced the initial hydrolysis reaction of TEOS. The hydrolysis reaction was faster in base catalyst system than in acid catalyst system. In acid catalyst, increasing the water concentration resulted in formation of a big primary particles in bulk SiO₂ gel. On the other hand, in base catalyst system increasing the water concentration didn’t form a bulk gel, which is due to the formation of segregated fine powders before the bulk gel transition.