The nonlinear bending behavior of piezoelectric bending actuator under strong electric field was studied.Considering the nonlinear piezoelectric effect of electrostriction and electroelasticity,a nonlinear relationship between the tip deflection or blocking force of the cantilever actuator and electric field is proposed.The calculated results show that the nonlinear prediction based on the nonlinear piezoelectric effect theory well agrees with the experimental results within a wide range of the electric field,while linear piezoelectric effect theory is only adaptable for the low electric field.