The influence of coal blending methods, such as out-furnace (external or premixed) blending and in-furnace (initially nonmixed) blending, with different excess oxygen (highest, medium, and lowest stoichiometric conditions) on unburned carbon and NOx emissions of blend combustion in an entrained flow reactor has been analyzed, using experimental and numerical approaches for binary coals used by Korean power plants. The results confirm that, under the medium condition, contrasting processes, such as reactive and unreactive effects, occur with SBRs in the out-furnace blending method. The in-furnace blending method results in an improvement in the efficiency of unburned carbon fractions and a further reduction in the NOx emission. Under the highest condition, the unburned carbon fraction in both the out-furnace and the in-furnace blending methods corresponds with the tendency under the medium condition with contrasting processes of lower magnitude, whereas the NOx emission in the highest condition increases slightly. Under the lowest conditions, the unburned carbon fraction in the out-furnace blending method gradually decreases as SBR. decreases, without a competition effect. The reduction Of NOx emission under the lowest conditions is more effective than those under other Conditions for the two blending methods because of homogeneous and heterogeneous NOx reduction mechanisms. These results show that the phenomenon that occurs with coal blending methods under different excess oxygen conditions has been demonstrated and the in-furnace blending method below medium conditions would be an effective method to improve combustibility and NOx emission due to penalty of NOx under the highest condition. In general, the numerical results are in agreement with the measured values and give insight into the phenomena that affect the blending Methods under different excess oxygen conditions.