  We developed the new parton model approach for exclusive semileptonic decays
of $B$-meson to $D,~D^*$ by extending the inclusive parton model, and by
combining with the results of the HQET, motivated by Drell-Yan process. Without
the nearest pole dominance ans\"atze, we {\bf derived} the dependences of
hadronic form factors on $q^2$. We also calculated numerically the slope of the
Isgur-Wise function, which is consistent with the experimental results.
