TiO2 catalyst in an internal-illuminated honeycomb photoreactor was prepared for Hg-0 removal from flue gas. The Hg-0 removal efficiency was above 95% under the optimal operation condition. With the increasing TiO2 coating value, the Hg-0 removal efficiency significantly increased. The catalyst calcined at 400 degrees C presented optimal Hg-0 removal performance, while higher calcination temperature weakened the Hg-0 photocatalytic removal activity. Similar He removal performances were obtained under UV irradiation when the reaction temperature was in the range 25-90 degrees C, and 1.5 mW/cm(2) of UV light irradiation was competent for Hg-0 photocatalytic removal. With the same quantity utilization of TiO2 catalyst, the internal-illuminated honeycomb photoreactor presented better Hg(0 )removal performance than the fixed-bed reactor. Finally, the procedure of Hg removal from flue gas over TiO2 catalyst in internal-illuminated honeycomb photoreactor was proposed, and the product in the He photocatalytic removal process was analyzed as well.