Fe74Al4Sn2P10C2B4Si4 powder were prepared by water atomization. It has been shown that this alloy has big glass-forming ability (GFA) and high stability against heating. Amorphous alloy powder can be got in size smaller than 400 mesh. Quality factor of the powder core made from this amorphous powder is remarkably higher than that of MPP in high frequency range, which means the core loss of the amorphous powder core is lower than that of MPP. The electrical resistivity of amorphous powder is much higher than that of MPP powder, that is why the amorphous powder core has lower core loss in the high frequency range.