Pure tungsten oxide thin films apparently show gasochromic performance, based on PdCl2 catalyst. In this paper, adulteration of MoO3 into WO3 sol has been achieved via sol-gel method. FT-IR, Differential Scanning Calorimeter (DSC-TG) and Uv-visible Spectroscopy have been used to analysis the compound sols, films and optical properties for the use of this material as smart windows. FT-IR shows that for the compound, new characteristic absorption bands arise, which is different from pure WO3 or MoO3. DSC-TG shows the phase change during the temperature ascending from 50 to 800°C. The compound thin films performs relatively well in coloring response time, colored extent, coloring-bleaching recycling and gasochromic effect with non-unicity color.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.