The slab method can predict rapidly the rolling force and torque in metal forming processes and a large amount of CPU time can be saved. Up to now, the work hardening effect has not been considered in the slab analysis for forging process of double-layer clad sheet. Evaluation of considering or eliminating the work hardening effect of material behavior in the slab analysis of three layer clad sheet forging process and investigating the subsequent effects on the process outputs are a novel subject considered in this paper. The pressure distribution as well as the forging force are investigated for both conditions. In addition, three layer clad sheet forging process is simulated entirely using ABAQUS/Explicit software. The results have showed that considering the work hardening will result into having larger stresses and forces in the process. Moreover, the results of considering the work hardening have better agreements with those from simulation. Finally, some experiments were performed on forging process of two layer Al/Cu clad sheet to evaluate the bonding quality of sheets. Therefore, forging process can be used for producing multi-layer clad sheets in various industries.