  We study the wave functions of light and heavy mesons in both hard-wall (HW)
and soft-wall (SW) holographic models which use AdS/CFT correspondence. In the
case of massless constituents, the asymptotic behaviors of the electromagnetic
form factor, the distribution amplitudes, and the decay constants for the two
models are the same, if the relation between the dilaton scale parameter and
the size of meson is an inverse proportion. On the other hand, by introducing a
quark mass dependence in the wave function, the differences of the distribution
amplitudes between the two models are obvious. In addition, for the SW model,
the dependences of the decay constants of meson on the dilaton scale parameter
$\kappa$ differ; especially f_{Qq}\sim \kappa^3/m_Q^2 is consistent with the
prediction of the heavy quark effective theory if \kappa\sim m_Q^{1/2}. Thus
the parameters of the two models are fit by the decay constants of the distinct
mesons; the distribution amplitudes and the \xi-moments are calculated and
compared.
