A multiphase reactive fluid dynamic model has been applied to simulate a complete chemical looping reforming (CLR) system, including an air reactor (AR), a fuel reactor (FR), a cyclone, and a loop seal. A two-fluid model with consideration of frictional stress between particles at high solid concentrations is used. A bubble-structure-dependent drag coefficient model is proposed and incorporated into the computational fluid dynamics (CFD) code to account for the effect of multiscale structures in the bubbling fluidized reactor. The predictions by the model are in good agreement with the experimental results. Flow pattern, profiles of bubbles, and distributions of gas compositions and temperatures are obtained. In addition, the influence of reaction temperature, operating velocity, and H2O/CH4 molar ratio on the gas concentration is also investigated.