Abstract: Pelletizing shaft furnace (PSF) is usually used to produce acidic pellet in China. A cold-state experimental set-up was built according to the principle of similitude, and then the flow-net diagrams with different constructional parameters were plotted to make sure of the gas flow distribution in PSF and how the gas flow distribution is affected by the constructional parameters. The results showed that among such constructional parameters the widths of vertical air internal channels, roasting zone and cooling zone and the heights of roasting zone, soaking zone and cooling zone are the main influencing factors on gas flow distribution in PSF. In case the width of internal channels or the height of roasting zone is increased or the width of roasting zone decreased, the upward cooling gas tends to decrease while the downward roasting gas tends to increase with the critical ratio of inflow k^* decreased gradually, and vice versa. It is important that the width of roasting zone is the key influencing factor on the uniformity of gas flow distribution in PSF. The results can be applied to the initial design of PSF especially in CAD.