  We investigate the valence quark distribution function of the pion
$v^{\pi}(x,Q^2)$ in the framework of the chiral constituent quark model and
evaluate the meson cloud effects on $v^{\pi}(x,Q^2)$. We explicitly demonstrate
how the meson cloud effects affect $v^{\pi}(x,Q^2)$ in detail. We find that the
meson cloud correction causes an overall 32\% reduction of the valence quark
distribution and an enhancement at the small Bjorken $x$ regime. Besides, we
also find that the dressing effect of the meson cloud will make the valence
quark distribution to be softer in the large $x$ region.
