The experiments were performed in a countercurrent packed column in a continuous mode to study the absorption of NOx and SO2 in urea solutions. On the basis of high SO2 removal efficiency, the NOx removal efficiencies under various experimental conditions were emphatically measured. The various influencing factors, such as urea concentration, temperature, initial pH value, oxidation degree of nitrogen oxides, SO2 concentration and additive on removal efficiencies of NOx were studied experimentally, and the optimal conditions were established. The reaction products were analyzed, and reaction mechanism and total chemical reaction equations for simultaneous desulfurization and denitration using urea solution were deduced. Molar reaction enthalpy, molar formation Gibbs function and chemical reaction equilibrium constant were calculated by thermodynamic methods. The calculation results show that the simultaneous desulfurization and denitration are available, and the removal efficiencies are 100% nearly. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.