  When taking the holographic principle into account, the vacuum energy will
acquire dynamical property that its equation of state is evolving. The current
available observational data imply that the holographic vacuum energy behaves
as quintom-type dark energy. We adopt the viewpoint of that the scalar field
models of dark energy are effective theories of an underlying theory of dark
energy. If we regard the scalar field model as an effective description of such
a holographic vacuum theory, we should be capable of using the scalar field
model to mimic the evolving behavior of the dynamical vacuum energy and
reconstructing this scalar field model according to the fits of the
observational dataset. We find the generalized ghost condensate model is a good
choice for depicting the holographic vacuum energy since it can easily realize
the quintom behavior. We thus reconstruct the function $h(\phi)$ of the
generalized ghost condensate model using the best-fit results of the
observational data.
