This paper presents a new H∞ control design approach of mixed eigenstructure assignment and H∞ filter for flexible structure vibration control. The new approach not only realizes the system dynamic response in time domain according to the state feedback gain matrix but also estimates the desired system state by H∞ filter and guarantees the performance specifications in frequency domain and robust stability. It is more effective in resolving the spillover problem for flexible structure vibration control and more simply in designing process. In this paper, an appropriate generalized plant is also constructed and deduced to a standard H∞ control problem based on feedback connection which guarantees both the realization of the controller and the optimization of performance specification. Effectiveness of the new approach is further validated by numerical simulation of vibration control for a cantilever beam bonded with piezoelectric actuators and sensors.