The Fe2CrSi nanostructured Heusler alloy was prepared by mechanical alloying followed by heat treatment. The structure, microstructure, and magnetic properties of the samples were studied by the following analysis methods: X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectrometry, transmission electron microscopy, and a vibrating sample magnetometer. The a-Fe (Si, Cr) solid solution with a disordered body centered cubic (bcc) crystal structure was obtained after 24 h of milling. An example of the sample milled for 32 h with a disordered crystal structure a-Fe(Si, Cr) was chosen to investigate the transformation with temperature using differential scanning calorimetry. The effect of annealing temperatures on the structural, microstructural, and magnetic properties of the ordered Fe2CrSi Heusler phase for the sample milled for 32 h was investigated.