In this article, the effects of several process parameters (energy density per unit solution, H2O2 concentration, NaOH concentration, gas flow, solution temperature, NO concentration, O-2 concentration, SO2 concentration, Fe2+ concentration and t-butanol concentration) on removal of NO from flue gas by UV (Ultraviolet)/H2O2 advanced oxidation combining with NaOH absorption (UV/H2O2/NaOH process) were investigated in a photochemical reactor. The results indicate that under all experimental conditions, SO2 can be removed completely. Increasing H2O2 concentration, NaOH concentration, energy density per unit solution, t-butanol concentration and low concentration of Fe2+ have a significant role in promoting removal of NO. NO removal efficiency sharply reduces with the increase of gas flow, NO concentration and high concentration of Fe2+. NO removal is slightly inhibited by increasing solution temperature and SO2 concentration, but is slightly enhanced by increasing O-2 concentration. Oxidation of NO by (OH)-O-center dot free radicals plays an important role in the removal of NO by UV/H2O2/NaOH process. NO3- is the final reaction product of NO removal by UV/H2O2/NaOH process. The reaction mechanism of NO removal by UV/H2O2/NaOH process has also been proposed. (c) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.