Based on the two-phase bubbling fluidized bed model, a quantitative analysis of the stationary characteristics of catalytic oxidation of naphthalene in a fluidized bed reactor was performed. Particular attention was paid to the selectivity of the process defined as the number of moles of anhydride obtained from one mole of naphthalene. It was found that the upper stable steady states are characterised by the lowest selectivity of the process analysed.