A threedimensional cold experimental model of a raceway was built based on the actual geometrical dimensions and operating parameters of the Number 5 blast furnace at Chongqing Iron and Steel Company in Chongqing, P.R. China. In the model, the fluid pattern was hypothesized as an incompressible viscous gassolid flow. A similar theory was employed to study the raceway forming mechanism and factors that influence the raceway. The results show the volume of blast, physical properties, height of burden layer and tuyere diameter have an effect on raceway size and shape. The penetration depth and height of the raceway expanded with increasing blast volume. As blast volume reached a critical value, the charging material on the top of raceway went upward and the spheroidicity raceway disappeared. At the same blast volume, the raceway penetration depth decreased with the increasing ratio of particle diameter to density. Although the height of the burden layer had little effect on the raceway penetration depth, it played a vital role in raceway height, which in turn increased as the burden layer height decreased. The tuyere diameter showed a greater influence on raceway penetration depth than the raceway height.