Test systems of piezoelectric stack actuator with and without mechanical load were designed. Maximum displacement and force were tested as 36.9 μm and 669.5 N under different frequency AC voltages application respectively. The equivalent stiffness of actuator was 20.9 N/μm according to the test result. In addition, the step response and hysteretic characteristics were tested. The rising time and setting time were obtained as 3 ms and 5 ms,which showed that the response speed could meet the requirements of vibration control of the precision platform. The results of hysteretic characteristics test showed that hysteresis nonlinearity must be considered in the vibration control of the precision platform.