SrTiO3 is a well-known efficient photocatalyst and has various industrial applications Such as water or air purification antibacterial agents and self-cleaning surfaces. In this work, pure SrTiO3 and Zr:SrTiO3 photocatalysts were prepared by the sol-gel method and then tested by scanning electron microscopy (SEM) and X-ray diffraction, respectively. The crystal phase of Zr:SrTiO3 shows a typical perovskite structure, in which Ti sites are substituted by Zr atoms, The as-prepared yellow Zr:SrTiO3 powders were then used as UV photocatalysts. Photocatalytic degradation activity of methylene blue over zirconium-doped SrTiO3 catalysts was tested under UV illumination. The high activity of Zr:SrTiO3 was due to the defects of its crystal lattice, thus the energy needed by the semiconductor photoproduction electron transition to the conduction band was smaller than the intrinsic absorption band. The optimal conditions Of Our experiments are as follows: under 8% doping density of Zr, 10 mg/l initial concentration of methylene blue, 0.15 g photocatalyst dosage, 6.5 of pH value and 4 h of UV illumination time, the degradation rate of methylene blue can reach 93.6%. (c) 2008 Elsevier B.V. All rights reserved.