The reduced TiO2 nanobelts are prepared through reduction of pure nanobelts by utilizing NaBH4. Compared with pure TiO2 nanobelts, the reduced TiO2 nanobelts present enhanced UV and visible photocatalytic performance in decomposing methyl orange (MO) and water splitting for hydrogen production. Experimental results and theoretical calculations show that the improved performance is due to the generation of Ti3+ and oxygen vacancy, which can increase the visible light absorption, promote charge carrier trapping, and improve photogenerated electron-hole separation efficiency, thus the photocatalytic property is improved. Moreover, the reduced TiO2 nanobelts with high ratio of Ti3+ (55.8%) present better photocatalytic properties than that of reduced TiO2 nanobelts with lower ratio of Ti3+ (9.8%), which indicates that a certain high ratio of Ti3+ will facilitate photocatalysis. The results show that the reduced TiO2 represent an effective strategy in improving the visible photocatalytic properties. (C) 2015 Elsevier B.V. All rights reserved.