Diatomites from different localities with different purities and diatom integrity as catalysts carriers were adopted to prepare TiO2 composite catalysts by a typical hydrolysis-deposition technique. The prepared composites were characterized by X-ray diffraction, N-2 adsorption-desorption, scanning electron microscopy and high resolution transmission electron microscopy. Through exploring the morphology and physical chemistry properties of the composite catalysts, it was indicated that the purity and diatom integrity of carriers could affect the dispersity and grain size of TiO2 nanoparticles. Compared with pure TiO2 and commercial P25 TiO2, the obtained composite photocatalysts exhibited better photocatalytic performance under the same conditions, and the RB decoloration rate of T-JL-PD can be up to 100% within 30 min. The higher activity of the obtained T-JL-PD photocatalyst should be attributed to higher purity and diatom integrity of carriers, which are in favor of the uniform loading of TiO2 nanoparticles. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.