Amorphous Fe-Mo po W-B alloy deposits have been made by electroless plating. The structure and the crystallization of the alloy have been studied by X-ray diffraction (XRD). It is found that the structure is amorphous if the boron content is within the range of 9. 8 at % to 27. 3 at %, which is wider than that of the binary Fe -- B, but narrower than that of ternary Fe-Mo-B amorphous film. A two-step crystallization process is observed for the deposits. At first, the crystalline phases a-Fe, Fe3B and (Mo,W)2B precipitates, followed by amorphous Fe3B, (Mo,W)B and Fe2(Mo,W) films form at high temperature Correspondent: Wang Lingling, Associate Professor, Department of Applied Physics, Hunan University, Changsha 410082, P. R.China, Tel: 086-731-8822351