Introduction: Structural and magnetic properties of ferromagnetic Fe thin layer films on Si substrates have been reported. We present topography features of these nanostructures films by atomic force microscopy (AFM). Characterization of magnetic domains and walls between them can be performed by using magnetic force microscopy (MFM) and alternating gradient field magnetometer (AGFM) instruments. The Fe thickness ranges from 50 to 150 nm. Our focus is to study systematically the effects of film thickness on magnetic anisotropy in thin films grown on semiconductor substrates. MFM images reveal stripe domain structure for the 100nm thick Fe on Si as well as hysteresis curves. The effective anisotropy shows oscillation for two types of Si substrates when the Fe films thickness increased.Aim: Our focus is to investigate systematically the effect of film thickness on magnetic hysteresis and effective anisotropy, especially in thin films grown on semiconductors substrates. For revealing stripe domain structure of Fe/Si (100) and Fe/Si (111), we use MFM pictures as well as hysteresis curves.Material and method: Fe thin films were deposited by thermal evaporation. Iron ingots from a 99.99 % purified Fe powder evaporated using an electron gun. The deposited Fe layer thicknesses vary from 50 to 150 nm. The crystalline structure of the deposited structures, X-ray diffraction method was used for investigation of nanostructure. Magnetic properties were also measured with MFM and experimental hysteresis loops were obtained by AGFM unit.Results: For Fe layer with 50nm thickness, Fe on Si (100) and Si (111) substrates, the Fe grows with (110) texture and has a bcc structure. The coercive field measured for the Fe films is about 100Oe. The measured hysteresis loops show that the coercive field decreases while the saturation field increases and such uniaxial anisotropy increases with increasing step density.Conclusion: Hysteresis diagrams show good ferromagnetic characteristics of these samples. The effective anisotropy shows oscillation, for two substrates Si types, when the Fe films thickness increased.