Abstract: This paper uses piezoelectric ceramics as actuators and sensors to suppress the vibration of flexible manipulator. Firstly,the experimental setup of the flexible manipulator is built. Secondly,from the identification of the system, the modal frequency of the system is obtained. Thirdly,experiment on active vibration control is carried out by using PD control method and PPF (Positive Position Feedback) control method. The experimental results prove that the method is effective in vibration suppression of flexible manipulator.