This paper analyzes and studies the key parameters of magnetic-valve controllable reactor（MCR）. Theimproper design of magnetic-valve section area will lead to control blind zone to a multi-stage saturable magnetic-valve controllable reactor（MSMCR）. In order to avoid this phenomenon

the design principle of the section area ofthe magnetic-valve is derived. Whether fully saturated for the iron core of the magnetic valve section is directlyrelated to the calculation of the MCR tap ratio. In order to ensure the full saturation of MSMCR

the calculationformula of the tap ratio is obtained by theoretical analysis The parameters setting principle of MSMCR model ispresented according to the equivalent n-h curve. The simulation results of MATLAB are accord with the theoreticalresults

validating that the parameters setting are right. This paper also provides the experimental results of two-stageMCR to verify the effectiveness of the theoretical analysis

which has guidance meaning for the design of MCR in reality.