This paper presents the plastic deformation behavior of bimetal composite rods during the axisymmetric and steady-state extrusion process through a conical die. In this study, the finite element code, DEFORM commercial package, considering frictional contact problem was used to analyze the effects for the diameter ratio of the core to sleeve layer on the material flow. Different cases of initial composite material are simulated under different conditions of extrusion process, which includes the semi-die angle, reduction in area and end distance, from the end of sleeve to the end of core, with constant value of reduction area, die corner radius and die land. The main design parameters influencing on deformation pattern are diameter ratio of the composite components and semi-die angle. Simulation results indicate that there is an obvious difference of forming pattern with various diameter ration and semi-die angle. The predicted forming load, the end distance and outer radius of sleeve of the rods are also obtained from numerical results. The analysis in this paper is concentrated on the evaluation of the design parameters on the deformation pattern of composite rod.