Silica films were prepared on the surface of polymethylmethacrylate (PMMA) via sol solution and solvothermal treatment, after modifying the surface of PMMA by solvothermal method. The samples were irradiated by atomic oxygen in a ground- based simulation system. The surface morphology and structure of silica films were investigated by atomic force microscopy, scanning electronic microscopy and attenuated total reflectance-Fourier transformed infrared spectroscopy. In addition, dry and wet thermal cycling tests were performed to investigate the adhesion behavior of silica films on PMMA. The results indicated that a uniform film was easily formed on the surface of PMMA. After atomic oxygen exposure, the silica film becomes more compact, without peeling off, and has good optical transparency. (C) 2012 Elsevier B. V. All rights reserved.