It is well known that the unmodelled dynamics may deteriorate the efficiency of a controller if the controller is not robust enough. This paper presents a robust H∞ vibration control method for high-speed flexible linkage mechanism systems with piezoelectric actuators and sensors. The robust H∞ controller is designed based on the complex mode and the H∞ control theory. The numerical simulation shows that the vibration can be significantly suppressed with permitted actuator voltages by the controller. The robust H∞ controller can avoid the spillover due to mode truncation to compare with some other method.