Abstract: Winding coil on primary side of the ferrite toroid forms an inductor. The permeability of the ferrite changes with various biasing DC current in coils on secondary side of the ferrite. Thus the inductance of the ferrite changes correspondingly. In the process of designing RF cavity of CSR，ferrite is used for the loading material of cavity. The characteristic of ferrite directly determinds whether the cavity can meet the requirements of the product design or not. The impedance of the cavity decides how much RF power should be got. At the same time, the impedance is in direct proportion to the μQf. Obviously the measurement of ferrite material is very important. This paper presents the measurement principle of permeability and Q-factor of ferrite, it also gives the concrete circuit and res