Abstract:A lot of experiments have proved the basic reason of the nonlinear and hysteresis constitutive curve in ferroelectric ceramics is domain switching. The micro domains witching behaviors of ferroelectric ceramics have been studied detailed. According to the physical experimental results and the classic equation of nucleation rate, a nucleation rate model is developed in order to get the evolution equation of the volume fraction of domain switching. The model is compared to nonlinear behaviors of ferroelectric ceramics. It turns out that the model can represent the typical nonlinear electromechanical coupling phenomena. The mechanism of domain switching of the nucleation rate model can further improve the macro phenomenological model.