The magnetostrictive characteristics of Fe-Al alloy thin films formed by an ion plating process were evaluated. An Fe-40 at%Al film showed α-Fe(b.c.c.) structure, although the Al content exceeded the solubility limit. Those results may be caused by a non-equilibrium condition with rapidly quenching of metal plasma gas phase to solid phase peculiar to ion plating process. The thin film of Fe-40 at%Al alloy prepared by ion plating showed higher magnetostriction than a film of pure Fe.