In order to enhance the photocatalytic activity of TiO2 which has a wide band gap width but a narrow range in light responsive region, a series of WO3/TiO2 composite photocatalysts with different composite proportions were prepared by a sol-gel method. The prepared samples were characterized by Scanning Electron Microscopy, N2 physical adsorption, X-ray diffraction, UV-visible spectroscopy and Fourier transform infrared spectroscopy. The effects of different composite proportions on the morphology, crystal structure, specific surface area and photocatalytic activity of WO3/TiO2 were investigated. The photocatalytic activity of the samples was evaluated by photo-catalysis water splitting under 300W Xenon lamp. In addition, the reaction mechanism over the composite catalyst was discussed. The results showed that, when λ was 300 to 600 nm, the absorbance of 2%-WO3/TiO2 was greater than the absorbance of TiO2, the absorption band edge was redshifted. As the composite ratio was 2%, the hydrogen photolysis aquatic activity of WO3/TiO2 was the best, with a highest value of 14445.3 μmol/(h·g), concentration of WO3 showed 10 times photocatalytic activity compared to pure TiO2. The photocatalyst technology would have extensive applications in the field of water splitting by solar light.