The dependence of the crystal structure and magnetic properties of iron films on preparation conditions has been investigated in detail by using a double‐ion‐beam sputtering system. During sputtering of an iron target by argon ions, the growing surfaces of iron films were bombarded by nitrogen or hydrogen ions with different kinetic energies below 500 eV. It has been found that these ions changed significantly the film structure and magnetic properties through the process of collision and reaction with iron atoms at the surface layer of growing film. As a result, the small amount of hydrogen or nitrogen added into iron films by ion bombardment improved effectively the soft magnetic properties of iron films. The iron films with saturation magnetization 4&pgr;Msas large as 22 kG and coercive forceHcas low as about 5 Oe were prepared by adjusting the accelerating voltage in the range of 100–300 V and the partial pressure of hydrogen or nitrogen in the range of 10−4–10−5Torr.