The ferrite electromagnetic shielding sheet with the size of 125 mm×125 mm and the least thickness of 50 μm were prepared by tape casting process.The magnetic spectrum of the ferrite and the performance of the electromagnetic shielding sheet under the condition of application have been studied.The effects of content of CuO and sintering aid Bi2O3 in the prescription of the material on the magnetic spectrum were also analyzed. The results indicated that the performance of the electromagnetic shielding sheet under the condition of application was related with the magnetic conductivity μ′and the value of Q of the material at 13.56 MHz.The magnetic spectrum would degrade when the content of CuO was too large.The magnetic properties of material at high frequency have little dependence with the additive amount of Bi2O3 in the prescription.