Visible-light-driven silver vanadate photocatalysts were synthesized using hydrothermal synthesis method. The structures of silver vanadates can be tuned by simply adjusting the hydrothermal time and adding the cetyltrimethylammonium bromide (CTAB). It is found that CTAB during the hydrothermal synthesis significantly affects the crystal structure, optical absorbance, and photocatalytic properties of silver vanadates. The pure silver vanadate oxides (SVO) consisted of mixed structures of Ag4V2O7 and α-Ag3VO4, with α-Ag3VO4 as the major phase. For the CTABadded sample, the α-Ag3VO4 phase was disappeared and the crystal phase of CTAB-SVO sample approached Ag4V2O7. UV-Vis spectroscopy indicated that silver vanadate particles had strong visible light absorption with associated band gaps in the range of 2.2-2.4 eV. The sample prepared at 140 °C for 4 h (HT4) exhibits the best photocatalytic activity using the apparent rate constant for initial photodegradation of gaseous isopropanol and the mineralization yield after long term light irradiation. The enhancement of photocatalytic activity up to 3 times was obtained using HT4 with respect to the P25 (commercial TiO2 photocatalyst). Surface characterization by Diffuse Reflectance Infrared Fourier Transform Spectroscopy confirms the presence of surface hydroxyl groups. The high activity can be attributed to the synergetic effects of strong visible-light absorption, favorable crystalline phase, and large surface hydroxyl groups.