Computational fluid dynamics (CFD) investigations have been carried out to understand the combustion and NOx emission characteristics in a 1000 MW pulverized-coal boiler, which is equipped with a dual-circular tangential-firing system in a single furnace. One group of separated over fire air (SOFA) nozzles has been widely studied and used in controlling the NOx emissions in a pulverized-coal boiler. In this work, a multi-group of SOFA nozzle arrangement is investigated for the NOx control and reduction. The predicted results agree well with the measured information from the full-scale boiler. The flow field, temperature distribution, species concentration, and char burnout are discussed. The relationship between the NOx formation and the SOFA arrangement are analyzed. The numerical results show that the multi-group of SOFA nozzle arrangement is an efficient method to control the NOx emissions in the pulverized-coal boiler, with few unfavorable effects on the coal burnout. The arrangement of the two-group of SOFA nozzles being in service presents better ability than the one-group arrangement in reducing the NOx emissions. The distance between the two groups of the SOFA nozzles should be longer for a better result of NOx reduction. The technology of air-staging combustion presented in this work is good to enhance the understanding of the NOx formation characteristics and useful for the NOx control and reduction in pulverized-coal boilers.