Abstract: The bulk multilayered Al/Fe-Mo-Si-B alloy with nanostructure was prepared by annealing the alternate layers consisting of metal Al and amorphous (Fe0.99,Mo0.01)78 Si9B13 alloy ribbons for 30 min at 873 K under pressure of 3~5.5 GPa. The structures and grain sizes of the Fe-MoSi-B nanocrystalline alloy were measured and analyzed. It was found that the pressure could restrain the growth of the grains and influence the formation of phases. The dependence of grain sizes for α-Fe(Mo,Si) and Fe2B on pressure was given. The morphologies of Al/Fe-Mo-SiB nanocrystalline alloy intedeces were observed by SEM. Two intedecial phases formed at various pressures were established by TEM and EDAX, and an unknown Fe-rich one with nanostructure was also observed. The dependence of the intedecial phases on pressure and its formation and growth mechanism were discussed