Circulating fluidized bed (CFB), due, to its unique advantages such as high fuel flexibility and low pollutant emission, has become a competitive technology for coal combustion. With the fast development of the computational fluid dynamics (CFD) technology, the numerical simulation has become a significant method to study the complicated characteristics of the CFB system. On the basis of a pilot-scale SO kWth CFB combustor, this Article develops a comprehensive three-dimensional CFB coal combustion model under the air atmosphere by the Eulerian Eulerian approach. Good agreement is observed for the general behaviors of the CFB combustor between simulated results and experimental data. A full-physics picture including flow structure, temperature, and gas composition in a three-dimensional space of the pilot-scale CFB combustor is provided. The simulation in this Article helps in a better understanding of the CFB combustion.