From experimental data for an iron powder and constitutive equations based on the modified Cam-Clay model, simulation of an axi-symmetric multi-stepped part has been achieved. In the first part of this paper, details of the constitutive relation are discussed. In the second part, the simulation of a compaction process for a multi-stepped part has been carried out. The phenomena arising along the compaction are thereby discussed: the piece rise from the lower punch during the compression and defects in the piece at the end of the compression. In the third part of this paper, results of numerical simulation are compared with experiments and it is shown that the forces exerted on the tools are in the same range of the experimental ones.