High temperature air combustion is a prospecting technology in energy saving and pollutants reduction. Numerical simulation on pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed was presented. The down-fired combustor, taken as the calculation domain, has the diameter of 220 mm and the height of 3000 mm. 2 cases with air staging combustion are simulated. Compared the simulation results with experimental data, there is a good agreement. It is found that the combustion model and NOx formation model are applicable to simulate the pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed. The results show that there is a uniform temperature profile along the axis of the down-fired combustor. The NOx emissions are lower than those of ordinary pulverized coal combustion, and the NOx emissions are 390 mg/m3 and 352 mg/m3 in Case 1 and Case 2, respectively. At the range of 300-600 mm below the nozzle, the NO concentration decreases, mainly resulting from some homogeneous reactions and heterogeneous reaction. NO concentration has a little increase at the position of 800 mm below the nozzle as the tertiary air supplied to the combustor at the position of 600 mm below the nozzle. High temperature air combustion is a prospecting technology in energy saving and pollutants reduction. Numerical simulation on pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed was. The down-fired combustor, taken as the calculation domain, has the diameter Compared with air staging combustion are simulated. Compared the simulation results with experimental data, there is a good agreement. It is found that the combustion model and NOx formation model are applicable to simulate the pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed. The results show that there is a uniform temperature profile along the axis of the down-fired combustor. NOx emissions are higher than those of ordinary pulverized coal combustion, and NOx emissions are 390 mg / m3 and 352 mg / m3 in Case 1 and Case 2, respectively. At the range of 300-600 mm below the nozzle, th NO concentration has a slightly increase at the position of 800 mm below the nozzle as the tertiary air supplied to the combustor at the position of 600 mm below the nozzle.