Different structural states - microcrystalline, submicrocrystalline, nanocrystalline (with a set of grain sizes each) and amorphous ones - of soft magnetic materials are considered. It is analyzed how the structural state of FesO^oSiisBio, FeeoO^oSisBis, C08i.5M09.5Zr9, and Fe73.5_xC0xCu1Nb3Si13.5B9 (x = 0, 10, 20, 30 at. %) amorphous alloys influences their magnetic characteristics in different nanocrystallization conditions. It is found that peculiarities of the fine structure and the grain size in the alloys under study correlate with their magnetic parameters and informative parameters of the Barkhausen effect.