  The optical potential without any free parameters for $^7$Li-nucleus
interaction system is studied in a microscopic approach. It is obtained by
folding the microscopic optical potentials of the constituent nucleons of
$^{7}$Li over their density distributions. We employ an isospin-dependent
nucleon microscopic optical potential, which is based on the Skyrme
nucleon-nucleon effective interaction and derived by using the Green's function
method, to be the nucleon optical potential. Harmonic oscillator shell model is
used to describe the internal wave function of $^7$Li and get the nucleon
density distribution. The $^7$Li microscopic optical potential is used to
predict the reaction cross sections and elastic scattering angular
distributions for target range from $^{27}$Al to $^{208}$Pb and energy range
below 450 MeV. Generally the results can reproduce the measured data reasonably
well. In addition, the microscopic optical potential is comparable to a global
phenomenological optical potential in fitting the presently existing measured
data generally.
