The master alloys of Fe87.5−xSi13.5Crx (x=0, 4, 8, 12at%) were prepared in vacuum induction melting furnace. Corresponding powder samples were obtained by 60h ball milling of the crushed master alloys, and studied by morphological, microstructural, electromagnetic and microwave absorption tests in the frequency range from 0.5 to 18GHz. The powders were characterized by a particle size less than 1μm and a grain size less than 100nm. In the cases of x≥8, Fe3Si phase with D03-type structure was observed, and the powders became amorphous completely. A crystallization temperature of 685K was found for x=8. Coercivity force and saturation magnetization of the powders decreased with the increasing of Cr content. As an electromagnetic wave absorbing material, the minimum reflectivity was −15.5dB at 8.5GHz and the absorption band was broad for x=8 powders.