To remove NO in flue gas, complex solution denitration is one of the most effective methods at room temperature. NO removal efficiency is related to the concentration of metal ions and ligands in the absorption solution. The experiments to remove NO in simulated flue gas were carried out by using iron complexation with EDTA disodium salt and sodium citrate as ligands. The NO removal efficiency was determined by mixing ammonium ferrous sulfate, disodium EDTA, and sodium citrate in various ratios. The experimental results revealed a 1:1:1 ratio as optimum for NO removal efficiency and cost-effectiveness of the process. By reducing and regenerating the absorption solution with zinc particles, the regeneration efficiency of Fe(II)L (L represents an amino carboxylic acid ligand) is above 70%, and the NO absorbed by the iron complex is reduced to form nitrogen and ammonium salt. The effects of different factors on the NO removal efficiency during the spraying process were investigated. The optimum conditions of absorption, i.e., a concentration of absorption solution of 0.05 mol/L, a temperature of 45 degrees C, a liquid-gas ratio of 10, and a pH of 6, were established. Under these conditions, the removal efficiency of nitrogen oxides was as high as 85%. The experiment confirmed that the NO removal efficiency is closely related to the concentration of Fe(II)L in the absorption liquid, and the removal efficiency decreases as the concentration of Fe(II)L in the absorption liquid decreases.