  We recalculate the pion electromagnetic form factor based on the perturbative
QCD formalism that includes the Sudakov resummation. We take into account the
evolution of the pion wave function in $b$, which represents the transverse
extent of the pion. An infrared enhancement is observed when $1/b$ approaches
$\Lambda_{QCD}$. We propose to freeze the evolution of the wave function at
some scale above $\Lambda_{QCD}$, such that perturbative contributions are
stablized. Our predictions are consistent with experimental data, and
insensitive to the variation of relevant parameters.
