Abstract: A large size CH3SiO3/2-SiO2 self sustained film with the thickness ranging from 50 to 1000 μm was prepared through sol-gel method by adopting CH3Si(OC2H5)3 and Si(OC2H5) as precursors.In this paper, the preparation processes of this thick film are discussed in detail and XRD technique was adopted for the identification of oligomer solution. Also, IR and AFM techniques were used to investigate the film structure and surface morphology