The catalytic ammoxidation of propane over V-Sb-Al catalyst in a circulating fluidized bed (CFB) is investigated, A mathematical model for the system based on combining the kinetics of reaction and the hydrodynamics of the bed is used to simulate the reactor performance. Sensitivity analysis of the effect of operating conditions shows that the acrylonitrile yield increases as reaction temperature increases or as propane feed mole fraction decreases. The acrylonitrile yield decreases as solid circulation rate, and gas superficial velocity increase.