In recent years, ionic liquids (ILs) have been widely used in extraction, synthesis, electrochemistry and other fields. Meanwhile, the environmental impact of ILs has been attracting a lot of attention, and eco-friendly treatment for ILs is becoming a necessary subject. In this study, photocatalytic degradations of benzothiazole ILs catalyzed by titanium dioxide (TiO2) and silver-loaded titanium dioxide (Ag/TiO2) were studied for the first time. The degradation of benzothiazole hexafluorophosphate ([C4Bth]PF6) could reach more than 99% within 240 min with the catalysis of TiO2. To improve catalytic efficiency, Ag/TiO2 was synthesized and characterized by UV-Vis diffuse reflectance ab-sorption spectra (DRS) and X-ray photoelectron spectroscopy (XPS). The degradation of [C4Bth]PF6 could reach more than 99% within 120 min in the degradation catalyzed by Ag/TiO2. The photodegradation products of benzothiazole ILs are composed of inorganic substances or organic substances with simpler structures, which are easier to decompose and less toxic. The degradation system proposed by this study could provide a simple, green, safe, and economical method for the efficient treatment of benzothiazole ILs.