Abstract: According to the dynamics of gas-solid packed beds, a mathematical model of gas flow in an air internal vertical channels (IVAC)/drying bed palletizing shaft furnace (PSF) is developed with certain boundary conditions. Using a manual program to solve the gas flow velocity field, the law of gas flow distribution in the PSF is investigated to discuss how the operating parameters affect the gas flow distribution. It is revealed that both the roasting and cooling air flow run radially at inlets and then run slantingly upwards or downwards into roasting-preheating zone inside IVAC. And the gas flow in the whole soaking zone is weakened. There are possibly three gas flow patterns in PSF, which are mainly dependent on the ratio of inflow, i.e., the greater the ratio is, the higher the downward roasting air flowrate and the lower the upward air flowrate will be. The critical ratio of inflow mainly depends on the constructional parameters and packed bed conditions of PSF.