Some Fe-Si alloys have been prepared using the mechanical alloying method. The structure of the obtained Fe-Si alloys is the same as that of the bcc α-Fe. The final powders mainly consist of some particles with a grain size from a few hundreds of nanometers to several microns,while these particles are composed of some subgrains with a microcrystalline size of about 15—20 nanometers. Their magnetic properties have also been investigated. The values of their specific saturation magnetization (σs) are slightly less than those of the corresponding single crystalline and polycrystalline Fe-Si alloys, while the values of their coercive force (Hc) are nuch higher than those of corresponding Fe-Si alloys in bulk. Their magnetic spectra are all relaxation type except for Fe75Si25, and the values of their μ′ and μ″ are comparable with those of the ferrite composite materials and, in their magnetizing process, the domain wall displacements are predominant.