TiO 2 /SiO 2 composite photocatalysts were prepared by depositing of TiO 2 onto nano-SiO 2 particles. X-ray diffraction (XRD), transmission electron micrograph (TEM), Raman spectrometer, UV–Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the properties of the synthesized TiO 2 /SiO 2 composites. These results indicated that the products without calcination were amorphous, and calcination could enhance the crystallinity of TiO 2 . Increases in the amount of TiO 2 would decrease the dispersion in the composites. H 2 O 2 -sensitized TiO 2 /SiO 2 composite photocatalysts could absorb visible light at wavelength below 550nm. The photocatalytic activity of as-prepared catalysts was characterized by methyl-orange degradation. The results showed the uncalcined composite photocatalysts with amorphous TiO 2 exhibited higher photocatalytic activity under visible light, and the activity of catalysts with TiO 2 content over 30% decreased with increasing of TiO 2 content. Increases in the calcination temperature and TiO 2 content promote the formation of bulk TiO 2 and result in a decrease in activity.