Disc extruders have been employed for blending, mixing, dispersing, coloring, homogenizing, degassing, and granulating of polymers. One of the difficulties in the design of disc extruders is the evaluation of dynamic characteristics such as required power, momentum transfer rate, and applied torque, which indeed indicates the capability of the machine and its components. In this paper the required conditions and model for developing of elastic deformation of polymers in the disc extruders are studied. By rheological modeling of disc extruders and related elements, dynamic behavior of this processing system which highly depends on elastic properties of polymeric materials is obtained. These data are necessary for a proper design the system, and more accurate calculation its moving parts.