The invention provides a positionable magnetic-core mounting fixture which comprises one electric plank, a plurality of troughs, antistatic rubber, magnetic-core limit bars, positioning pins and a foot pad. The positionable magnetic-core mounting fixture is characterized in that a magnetic core is limited by the aid of the magnetic-core limit bars, and deflecting of the magnetic core during mounting is prevented. The positionable magnetic-core mounting fixture is simple in structure, the magnetic core is controllable in position, and tolerance value of inductance is reduced.