The effect of water quenching on initial and maximum permeabilities of Fe-Al alloys in the range of the superstructure (Fe3Al) have been measured with the forged specimens. The curves of initial and maximum permeabilities to the quenching temperature show generally a maximum range which exists in the vicinity of the temperature of super-lattice transformation; the latter curve has another maximum, range which situates in the higher temperatures. The initial permeability of an alloy_??_containing 13.92% aluminium reaches 3500 when quenched from 550°, and the maximum permeability of an alloy of 15.29% aluminium content, 34300 when quenched from 700°. The smallest value of hysteresis loss and coercive force obtained by the present experiment is 68 ergs/cm3 and 0.03 Oe respectively; the highest value of speific resistance is 144μΩ/cm3. From these facts, it is easily understood that the magnetic of iron-aluminium alloys are improved when quenchedl from the of transformation temperature as in the case of permalloy; these alloys may be used instead permalloyaccording to circumstances. Thus thel present investigators have named. these alloys “Alperm”.