In this paper, Stöber process with high concentration of TEOS up to 1.24 M is implemented to prepare submicrometer particles, and we successfully increase mass fraction up to 7.45%, which is 1.85 times as large as that can be obtained in Wang et al.’s experiment. The reaction conditions including TEOS, NH3, H2O, solvents, temperature, and the formation mechanism of particles are also investigated.