Abstract: SiO2 xerogel was prepared by sol-gel process and azeotropic distillation drying method. The effect of azeotropic disstillation process on the formation of gel porous network structure under ambient pressure was discussed, and the changes of xerogel phase and pore structure during calcining process were investigated. The results showed that the particle surface hydrophobic modification and solvent replacement can be simultaneously completed during azeotropic distillation drying process. After calcined at 300°C, the specific surface area and pore volume of SiO2 xerogel is 924.62 m²·g^-1 and 0.754 cm³·g^-1 respectively, and the pore size distribution is mainly less than 10 nm, which are similar to aerogel in microscopic structure. High temperature is the direct factor of changing particles sinter and pore structure.