The feed wedge gap of the cold feed extruder was simplified into a linear wedge region, and the feeding process was dynamically simulated by using the Bird-Carreau constitutive model. The images of the pressure distribution along the wedge direction, and the pressure and velocity distribution on the cross section of the wedge region were obtained. The simulation results were compared with the previous test data and the calculation results based on the Newton constitutive model. Through comparison, it is found that they all have similar change trends. The simulation results along the wedge direction are smaller than the calculation results but larger than the test data, and at the entrance of the wedge area, both the simulation results and the test data have pressure values. The simulation results of the pressure and velocity distribution on the cross section of the wedge-shaped area are smaller than the calculation results. The research in this paper shows that although the existing calculation methods based on Newton""s constitutive model can roughly analyze the dynamics of the feeding process, the more accurate dynamic model of the feeding process must consider the non-Newtonian behavior of the rubber compound and the appropriate boundary conditions on the surface of the barrel.