The invention discloses a live-operated direct current bias magnetic current measurement instrument for a transformer neutral point and belongs to the field of transformer measurement. According to the live-operated direct current bias magnetic current measurement instrument for the transformer neutral point, when a transformer measurement operation is performed, two cases occur, one case is as follows: the operation is performed at the bottom of a busbar; at this time, a compression gas rod does not need to start, only an open-close switch needs to be directly started, after the open-close switch is started, a stepping motor starts to work, a rotating shaft is driven to drive a rotating spin rod to rotate in a rotating shell so that a rotating auxiliary rod moves forward, and a moving block is driven to start moving so that the distance between a stationary block and a moving block increases until the distance reaches the busbar width, then the open-close switch is disconnected so that the stepping motor stops working; at this time, a power spring starts to work to drive the rotating spin rod to rotate in a reverse direction in the rotating shell so that the rotating auxiliary rodmoves backward and a current sensor is stuck on the busbar.