[en] The interaction cross sections of medium and high energy nucleus-nucleus scattering are studied with the Glauber Model and Hartree-Fock type variational calculation. The interaction cross sections so obtained nicely satisfy the additivity relationship, which in turn suggests the existence of a nuclear interaction radius in nucleus-nucleus scattering. With the calculated interaction cross sections, the nuclear interaction mean free path of high energy nucleus in emulsion is studied, and the results agree very well with experimental data. It is found that the interaction radius of the projectile nucleus can also be determined from emulsion experiment. (author)