With a two-site Hubbard model and Floquet theorem, we investigate the dynamic behaviour of an exciton confined in a coupled double-quantum-dot system driven by an alternating current(AC) electrical field. The calculation shows that the quasi-energy levels versus the amplitude of the external field undergo a series o f exact-crossing and avoid-crossing. Generally, the initially localized state can remain forever at the first exact-crossing point of two ground quasi-energy levels. Increasing the interaction of the electron and hole, the degree of dynamical localization is enhanced. At the second exact-crossing point of ground quasi-energy levels, this kind of dynamical localization is decayed. At the point of avoid-crossing and offset from the exact-crossing, the dynamical localiz ation ceases to maintain. This demonstrates the possibility to control the excit on states on extremely short time scales using the appropriate AC field with the adjustable amplitude and frequency, which may be useful for quantum information processing.