On the basis of practical size and operating parameters of the No. 5 blast furnace in Chongqing Iron and Steel Company Limited, assuming that flow in the blast furnace raceway is a gas-solid flow and gas is viscous and incompressible fluid, three-dimensional cold experimental model of blast furnace raceway was established according to similarity theory, and effect factors of raceway size were analyzed. The results are demonstrated as the following: blast flow rate, physical properties of charging material, height of charging material and tuyere diameter have effect on size and shape of raceway. With increasing of blast flow rate, penetration depth and height of raceway increase to some different degrees. When blast flow rate is big excessively, material bed is rising and ellipsoidal raceway shape is damaged. The height of material bed has a little effect on raceway penetration depth, but raceway height diminishes gradually with height of material bed increasing. Tuyere diameter has remarkable influence to raceway penetration depth.