NO emitted from coal combustion was harmful to the environment. For most current wet denitrification technologies, obtaining the desired removal efficiency was always dependent on the contact time of NO with the reaction solution. In this paper, a novel Fe/NaOH/H2O2 technology was proposed to remove NO, which could obtain 90% NO removal efficiency when the flue gas residence time in solution was 3 s. The mechanism of H2O2 decomposition and NO removal were analyzed. Results demonstrated that Fe and NaOH together catalyzed H2O2 to produce radicals, and ⋅O2− radicals took the main responsibility in the process of NO removal. NO3− and NO2− were the final forms of NO. In addition, the effects of several common experimental parameters were investigated on the NO removal performance. The increase of H2O2 concentration, Fe concentration, solution pH and reaction temperature all had a positive effect on NO removal, but this process was also accompanied by an intensification of the useless decomposition of H2O2 (consumption of H2O2 in the form of O2). The addition of SO2 to the flue gas had a slight effect on the NO removal and the useless decomposition of H2O2.