The metal-ferrite composites FexCo(1-x)/CoyFe1-yFe2O4 are synthesized by using disproportion of Fe (II) and reduction of Co (II) by Fe-0 under hydrothermal condition. The size of the particles of the composites decreases as the [KOH] decreasing. The composites are measured by TEM and it can be deduced that when [KOH] = 0.1, the size of the alloy body-centered cubic (BCC) in composites is 20 +/- 7 nm, the size of the Cobalt ferrite (spinel) is 170 50 nm. The maximal value of the saturation magnetization (Ms) of the composite is about 100.14 emu/g, which is synthesized under Co (II)/Fe (II) = 0.05, [KOH] = 1 N, T = 150 degrees C and t = 3 h. The value of Hc of the composite synthesized under Co (II)/Fe (II) = 0.5, t = 3 h, T = 150 degrees C and [KOH] = 10.2 mol/L is about 2878.19 Oe. The Fe-Co alloy is synthesized through a reduction reaction of the composites in a flowing gaseous mixture. There is a maximal value (302.9 emu/g) of the Ms for the alloys generated at 1000 degrees C, which is the Co0.412Fe0.588 alloy. Crown Copyright (c) 2009 Published by Elsevier B.V. All rights reserved.