Abstract: Composite TiO₂-SiO₂ photocatalysts were prepared by sol-gel method using SiO₂ aerogel as carrier. The composite catalysts were characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction and specific surface area and pore structure analysis. The results show that TiO₂ particles are uniformly distributed on the surface of SiO₂ aerogels,and the catalysts have abundant spatial pore structure and good specific surface area. Based on the single factor experiments and the response surface optimization experiments,the optimum technological conditions for the preparation of composite catalysts sre obtained as follows:the ratio of tetraethyl orthosilicate（TEOS）to water（V/V）is 4:1,the concentration of TiO₂ in suspension was 2.21 g/L,and the sol-gel time is 3.1 days. The composite catalyst prepared under the optimum conditions is used to degrade 10 mg/L methylene blue solution for 24 hours,and the removal rate reaches 99.1%.