Ni-Zn ferrite powder with different composition were prepared by Sol-gel process using Fe(NO₃)3·9H₂O, Ni(NO₃)2·6H₂O, Zn(NO₃)2·6H₂O, citrate acid and ammonia as raw materials. The thermal decomposition behavior of dried gel and crystallite size of synthesized powders were studied by using TG-DTA and XRD. Moreover, the relationship of ferrite composition on electromagnetic properties were investigated by network analyzer. The results reveal that the imaginary part of permeability of synthesized powders decreases with frequency and the content of Zn in the Ni-Zn ferrite powder.