This paper investigates the feasibility of direct model reference adaptive control (MRAC) scheme for the vibration suppression of a smart flexible beam. Direct model reference adaptive controller whose parameters are updated directly from the Lyapunov-based adaptive laws is developed. The adaptive laws for updating the controller parameters are derived and the stability for the closed loop system is proved. The developed MRAC design is numerically verified on a flexible beam model, showing that it has better performance and robustness in vibration suppression with respect to the system parameter variations. Compared with classical active vibration control such as positive position feedback (PPF) control, MRAC can produce more efficient and faster control than PPF control. The satisfactory simulation results show that the MRAC scheme is an effective approach for vibration suppression.