Nonlinearity between exciting current and output displacement spoils magnetostrictive actuators’ performance. Chaotic nonlinearity is an important aspect of nonlinear character for magnetostrictive actuators. To explore the erratic behaviors of the actuators, a nonlinear dynamic model was established. The bifurcation diagrams, Lyapunov exponent, phase portrait, Poincaré mapping diagrams, amplitude spectrum, etc., which demonstrate dynamical characteristics of the system were obtained by numerical integration. Analysis indicates that under the condition of low frequency range, chaos would appear when exciting current is high and stiffness of the system is relatively low. 