Abstract: For the case that the overall gas-solid reaction in a pellet in a packed bed is controlled simultaneously by the chemical reaction on the reaction front and the intraparticle diffusion, the interaction between compressible flow and isothermal gas-solid reaction in the packed bed was investigated.On one hand,both the mass and density changes of the gas mixture due to chemical reaction affected the motion of gas mixture considerably, on the other hand, the flow of gas mixture also affected the gas-solid reaction.A coupled model was presented to formulate these interactions.A numerical solution showed that the velocity profiles obtained from the coupled models were very different from those obtained with the existing non-coupled model, not only in magnitude but also in the trend of velocity variation in the packed bed.Because the ignorance of the density change of gas mixture due to reaction would lead to an extra sink of gas mass dissipation or a source of gas mass generation, the effect of the density change of gas mixture on itself flow could not be neglected, especially in the situation where there was an observable difference between the molar masses of reactive gas and inert gas.The numerical results further showed that the concentration profiles obtained from the coupled models differed greatly with those obtained with the non-coupled model, and the progress of the concentration wave front of reactive gas obtained from the coupled models was obviously different from that obtained with the non-coupled model.It was found that chemical reaction blocked greatly the progress of concentration wave front of reactive gas.If the average pressure drop across a packed bed and the other conditions were kept unchanged, the longer the packed bed, the shorter the normalized distance of wave front advance.The evolution of the active reaction zone in a packed bed affected the velocity profile of gas mixture considerably.