The utility model relates to a master iron core monitoring and current -limiting control system based on sensor able to programme, but including a plurality of programming current sensors, each but the programming current sensor all is connected with a signal pickup assembly electricity, the concentrator is connected to the signal pickup assembly electricity, analog/digital device is connected tothe concentrator electricity, microprocessor is connected to the analog/digital device electricity, the display is connected to the microprocessor electricity, each but programming current sensor still electricity is connected with current -limiting resistor device, each the current -limiting resistor device with the microprocessor electricity is connected. The utility model discloses a but masteriron core monitoring and current -limiting control system include the programming current sensor, can set up the scope of measuring current flow and frequency to but realize the safety inspection ofprogramming current sensor, it includes still that the current -limiting resistor device can handle the current abnormality condition, with the safe operation of ensureing the transformer.