Two series of isotropic nanostructured Fe-Pt permenent magnetic thin films have been prepared by sputtering Fe/Pt multilayers and subsequent vacuum annealing. Their structures and magnetic properties have been inverstigated. Studies show that Fe-Pt permenent magnetic thin films with Fe-rich were composed of two phases: a hard FePt phase and a soft Fe3Pt phase. Saturation magnetic polarization and remaenence increase with increasing thickness of the Fe layer. Kelly-Henkel plot indicates that magnetic interactions in Fe-Pt thin films are mainly determined by ferromagnetic exchange interaction between neighboring grains.