Ag-modified TiO2 nanotube arrays (Ag/TiO2 NAs) were prepared and employed as a photocatalyst for degradation of 17α-ethinylestradiol (EE2) and inactivation of Escherichia coli. The as-synthesized Ag/TiO2 NAs were characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). It was found that metallic Ag nanoparticles were firmly deposited on the TiO2 NAs with the pore diameter of 100 nm and the length of 550 nm. Photocatalytic degradation of EE2 and inactivation of E. coli were enhanced effectively in an analogical trend using Ag/TiO2 NAs. In particular, Ag/TiO2 NAs exhibited the antimicrobial activity even in the absence of light. The Ag acted as a disinfection agent as well as the dopant of the modified TiO2 NAs photocatalysis by forming a Schottky barrier on the surface of TiO2 NAs. Inorganic ions suppressed the rates of photocatalytic degradation of EE2, with HCO having a more pronounced effect than NO or SO. Humic acid (HA) was found to increase the rate of EE2 degradation.