In this letter, a Schottky diode ultraviolet (UV) detector based on TiO2 nanowire (NW) array with Ag electrode is fabricated. The TiO2 NW array was prepared via a low-temperature hydrothermal method and characterized by means of X-ray diffraction, scanning electron microscope, and XPS. The Schottky barrier character of Ag/TiO2 contact was researched in detail. At -5-V bias, the dark current of the detector was less than 35 nA. Under the irradiation of 350-nm UV light, a high responsivity of 3.1 A/W was achieved due to the internal gain. The Schottky diode detector with simple fabrication process, low cost, and superior performance would provide a new way in fabricating UV imaging arrays.