Poling processes of ferroelectrics by an electric field in addition to a mechanical load transverse to poling direction is simulated by microstructural FEM based on the nonlinear constitutive model of Huber et al. (1999). Observation of the evolution of domain switching shows that the compressive stress apparently enhances the degree of switching aligned with the poling direction. As a macroscopic response, the additional application of compressive stress significantly improves the electromechanical coupling effect. In the present numerical investigation, the enhancement of the coupling coefficient K 33 of BaTiO 3 exceeds 10%.