Abstract: By the method of FEM,the chracteristics of a DE actuator subject to a voltage and biaxial pre-stretches are simulated. Relations between the nominal electric field with the stretches,the nominal electric field with the nominal electric displacement and the true electric field with the stretches are analyzed. The simulation results get along well with the results obtained by the theoretical model. Relations between parameters of electric field induced strain limit,electric field intensity and electric displacement are analyzed based on the state equation obtained when DE is biaxially pre-stretched. The results show that the stability of the actuator is markedly enhanced by prestresses; the method used in the FEM can be used in the design of DE actuators with biaxial pre-stretch.