$TiO_2$ Powders were prepared by sol-gel method to testify the characteristics as the photocatalysts. The relationship between processing conditions (R-value (molar ratio of water to alkoxide)), heat treatment temperature, microstructures (crystalline phases), and properties (surface area, particle size) was examined. The optimal conditionsto improve the activity of photocatalyst for photobleaching of dyes in aqueous solution, Were determined.