  A systematic analysis shows that the main uncertainties in the form factors
are due to the twist-3 wave functions of the light mesons in the light-cone QCD
sum rules. We propose an improved approach, in which the twist-3 wave functions
doesn't make any contribution and therefore the possible pollution by them can
be avoided, to re-examine $B \to \pi$ semileptonic form factors. Also, a
comparison between the previous and our results from the light-cone QCD sum
rules is made. Our method will be beneficial to the precise extracting of
$\mid{V_{ub}}\mid$ from the experimental data on the processes $B \to \pi \ell
\widetilde{\nu_\ell}$.
