Active vibration control (AVC) effect of the classical strategy is mainly restricted to a limited region around the error sensor, while the structural vibration at other locations may be dramatically enlarged. The enlargement is non-negligible when the global vibration suppression is considered. Aiming at this enlargement, an indicator is presented to reveal the effect of the classical strategy on the whole controlled structure. By establishing a cost function related with the indicator, an improved AVC strategy is proposed. Utilizing the proposed strategy, an optimized secondary force is obtained to achieve the global vibration suppression. Numerical simulations of AVC are undertaken on a typical plate to verify the superiority of the proposed strategy. Results demonstrate that the proposed strategy is still effective to achieve the global vibration suppression at frequencies where the classical strategy fails. This performance indicates that the proposed strategy is advantageous for global vibration suppression by attenuating the total input power, which provides more attraction for the actual application of AVC.