  The squeeze-out flow in reactions of $^{124}$Sn + $^{124}$Sn and $^{124}$Ba +
$^{124}$Ba at different incident energies for different impact parameters is
investigated by means of an isospin-dependent quantum molecular dynamics model.
For the first time, it is found that the more neutron-rich system ($% ^{124}$Sn
+ $^{124}$Sn) exhibits weaker squeeze-out flow. This isospin dependence of the
squeeze-out flow is shown to mainly result from the isospin dependence of
nucleon-nucleon cross section and the symmetry energy.
