The alloying of 6.5wt% Silicon in iron decreases the magnetization and the anisotropy and minimizes the iron loss noticeably. But it is very difficult to make thin sheets because of its poor ductility which is due to an ordering reaction (body centered cubic to CsCl type crystal structure). However the ordering reaction can be suppressed by rapid solidification method. The cooling rate of rapidly solidified Fe-6.5wt% Si alloy is about 10³K/s and rapidly solidified structure are fine structure, cellular structure, dendrite and equiaxed grain from surface. The precipitates of DO₃Phase emerges on B₂matrix and the coercive force was 0.51 Oe (50cycle, 15KGauss) in Fe-6.5wt% Si alloy which was processed by heat treatment of 1150℃ for 1hr in high vacuum.