The squeeze-out flow in reactions of Sn-124 + Sn-124 and Ba-124 + Ba-124 at
different incident energies for different impact parameters is investigate
d by means of an isospin-dependent quantum molecular dynamics model. For th
e first time, it is found that the more neutron-rich system (Sn-124 + Sn-12
4) exhibits weaker squeeze-out flow. This, isospin dependence of the squeez
e-out flow is shown to mainly result from the isospin dependence of nucleon
-nucleon cross-section and the symmetry energy.