A pole assignment method is proposed for piezoelectric shunt damping circuits as passive control. An electromechanical coupling equation for the piezoelectric shunt damping system is established. Considering the modal displacement as the output, the characteristic equation of the system pole is obtained. The optimized object is determined by making use of the characteristic that the distance between the dominant pole and the imaginary axis plays a key role in the attenuation of the dynamic response of the system. And then the optimal value of the parameters of the piezoelectric shunt damping circuit is solved. Finally, the optimal method is tested by numerical simulation, and compared with the conventional transfer function optimization method. The simulation results show that the piezoelectric shunt circuit designed by the pole placement method has a good effect of suppressing the vibration. This verifies the validity of the pole placement method.