In many applications, porous SiO2 thin films with high permeability and hydrothermal stability are highly desired. We synthesized mesoporous SiO2 thin films by sol-gel processing using non-ionic surfactants (F127 and C18EO10) and mixed surfactants as templates. N2 sorption, x-ray diffraction and TEM were used to characterize the porosity, pore size, and pore structure. The effects of surfactant composition on film pore structure, pore size, and its hydrothermal stability were studied. Our results show that films with hexagonal phase and worm like structure can be prepared using F127 and C18EO10 surfactants respectively. Films made using F127 showed greater hydrothermal stability, but lower permeability, than the films prepared using C18EO10. By mixing these two surfactants and adjusting their ratio, a transition from hexagonal phase to worm like structure was observed. This ratio can be tuned to optimize the permeability and hydrothermal stability of the film as needed for various applications. With certain F127 to C18EO10 ratios, we were able to synthesize films with both high permeability and hydrothermal stability. The effect of Al2O3 incorporation on the pore structure, hydrothermal stability was also studied. Our results show that the film hydrothermal stability can be improved by incorporation of Al2O3 in to the film.