Relationship between the effect and the amount of SiO2 addition on the photo-generated hydrophilicity of TiO2 films isinvestigated. X-ray diffraction, UV-Vis spectrumand Fourier transform infrared spectroscopy are used to determine film behaviorand the hydrophilicity is assessed by contact angle measurement. It is found that addition of 40 mol% SiO2 to TiO2 is mosteffective for reducing the contact angle of water. The contact angle of water can maintain low for a long time in dark place.SiO2 addition has a suppressive effect on the crystal growth of TiO2 in calcination and enhances the transmittance of thecomposite films. SiO2 and TiO2 form single oxide particles in the films, but a part of complex oxide may be formed. Ti-O-Sibonds increase the acidity which induces the increasing of the hydroxyl content in the composite films.