The effects of frequency, volume fraction of ferrite, and particle size on the electric and magnetic properties of epoxy composite containing Ni- Zn ferrite were investigated. The composites were prepared by the cement mixed method and shaped as coaxial, toroidal, and disc types. The complex permeability and permittivity were obtained using an Impedance/Gain phase Analyzer(HP4194A) and a Network Analyzer(HP8753C) in the frequency range from 1 MHz to 5 GHz. The complex permeability of the composites increased with increasing the amount of ferrite. Especially the complex permeability of the composite showed the frequency dispersion chracteristic. A model to describe such phenomenon was proposed. The complex permittivity of the composite mainly depended on the volume fraction of the filler and was relatively independent on the frequency and the particle size of filler.