Abstract: The mechanical alloying effects on the structures of Fe71.3AI28.4(CeO2)0.3 and Fe73.3AI9.8-Si,e.e(CeO2)0.3 samples have been investigated mainly by Mossbauer spectroscopy and X-ray diffraction. It is found that with the increase of milling time, a substituting disordered a-Fe solution is formed gradually and almost completed after milled for 72 h. Further increasing milling time causes the atomic rearrangement within the powders. Correspondingly' the average lattice parameter and average crystalline size change until 72 h and remain constant after 72 h. The addition of Si leads to the higher disordered degree reflected in the smaller average hyperfine field and larger mean Square deviation.