Based on TEOS system and sol-gel process,using solvent alcohol together with catalysts,the microstructure of SiO2 particles in the sol was exactly controlled.Silica coatings were prepared on glass and annealed.The films were characterized by ellipsometer and scanning electronic microscope respectively,the effect of Catalytic agent was investigated,the experimental results show that adjusting catalytic agent can effectively effect the structure of SiO2 thin film.