Abstract: Considering the influence of mechanical factors and combustion reaction in a blast furnace on the tuyere raceway,two mathematical models,a static model and a dynamic model,were proposed in order to describe the penetration and variation rules of the raceway.Simulated results show that the static model is able to predict raceway penetration accurately,and the dynamic model can describe the dynamic process of raceway penetration with time when the blast velocity changes.Finally the formation and variation rules of the raceway are concluded as the following:the fast movements of the packed bed driven by blast pressure make the raceway size vary rapidly and then the raceway prototype is formed.In addition,combustion reaction repairs the size and shape of the raceway so as to maintain a stable raceway.In the entire change process of raceway size,frictional forces are proved to play an important role for raceway stability.Predictions of the mathematical models are in reasonable agreement with the measured data of blast furnaces and other researchers' experimental results.