In this work, the Z-type barium ferrite of single phase was prepared by the salt-molten method which was a novel, economical and environmentally friendly method. The results showed that the salt was helpful to get single phase and could effectively modify the shape of the powder. Based on the microwave measurement, reflection losses exceeding −20 dB of Co2Z composite were obtained in the frequency range of 4.1–14.5 GHz for absorber thicknesses of 2.1–3.5 mm and the minimum value of the reflection loss was -42.9 dB at 4.9 GHz for the thickness of 2.9 mm. For those unique properties, Co2Z could be a good candidate for electromagnetic (EM) materials and other practical applications at the high frequency.