A novel capillary array photocatalytic reactor (CAPCR) was developed and the photocatalytic performance towards degradation of azo dye, methyl orange (MO), as a probe pollutant was systematically studied. The TiO2 films were prepared using a sol-gel method and the inner wall of the capillaries was overlaid with a gas pressure-operated device. Higher surface area for catalyst coating per unit reactor volume was obtained in the CAPCR, and an increase in contact between target compounds and photocatalyst. There improvement allowed for much more specific reactor capacity. The TiO2 films were characterized by field emission scanning electron microscopy, X-ray diffraction, and UV-vis absorbance spectra. The optimized experimental conditions for MO degradation in CAPCR were investigated. The CAPCR showed better removal efficiency for MO degradation than that in a conventional batch reactor with P-25 TiO2 powder and TiO2 film immobilized onto a quartz tube. (C) 2011 Elsevier B.V. All rights reserved.