In this study, a titanium dioxide (TiO2) nanowire array photoanode was successfully grown on titanium sheet in acidic vapour phase in a hydrothermal reactor. The preliminary results from scanning electron microscopy suggest that the obtained TiO2 nanowire array was rooted directly on the titanium substrate, while the X-ray diffraction indicated that it consists of rutile nanocrystals without the need for calcination. In comparison with rutile nanorod array (RNR-TiO2) photoanode grown on a FTO glass substrate, the as-prepared rutile nanowire array (RNW-TiO2) photoanode shows higher photoelectrocatalytic activity toward oxidation of organic compounds. The as-prepared RNW-TiO2 photoanodes are capable of oxidizing a wide spectrum of organic compounds such as glucose, fructose, glutaric acid, malonic acid, and glycine indiscriminately in aqueous solutions in a bulk photoelectrochemical cell. An excellent linear relationship between the obtained net photocurrents and the equivalent concentrations of organic compounds suggests that the RNW-TiO2 photoanode could be a versatile sensor for the determination of organic compounds.