  We investigate the associated production of a scalar Higgs boson ($h^0$ or
$H^0$) with $Z^0$ boson in the minimal supersymmetric extension of the standard
model (MSSM) at the CERN Large Hadron Collider (LHC), including the
contributions from $b\bar{b}$ annihilation at the tree level and gluon fusion
via quark and squark loops. We quantitatively analyze the total cross sections
in the mSUGRA scenario. For the production of $h^0$ associated with $Z^0$, we
find that in most of the parameter regions, the contributions from initial
$b\bar{b}$ and $gg$ are at a level of one percent of the total cross section
and therefore almost insignificant. For the production of $H^0$ associated with
$Z^0$, the contributions from $b\bar{b}$ channel can be much larger than those
from light quark initial states. Especially for large $\tan\beta$, the
increment can reach about one order of magnitude. Thus, when considering the
associated production of $H^0$ and $Z^0$ at the LHC, the contributions from
$b\bar{b}$ annihilation should be taken into account seriously.
