The invention discloses a voltage regulating control device for an on-load tap changer, which comprises an on-load tap changer, a voltage regulating control device, and a voltage regulating transmission device, wherein the on-load tap changer is used for being accessed to external AC and outputting distribution network voltage to an external load after transformation; the voltage regulating control device comprises a power adaption module, a microcontroller, and a voltage sampling module; the voltage regulating transmission device comprises a stepper motor, a gear device and a rack; the power adaption module is connected with an external power supply for converting voltage of the external power supply to provide power; the voltage sampling module is accessed to the distribution network voltage for sampling the distribution network voltage, generating a sampling signal and sending the signal to the microcontroller; the microcontroller is connected with the stepper motor for receiving the sampling signal and controlling rotation of the stepper motor; the stepper motor enables the gear device to rotate through rotation; the rack is engaged with the gear device, the rack moves linearly through rotation of the gear device, and an adjustable transformer tap is fixedly arranged on the rack, and the transformer tap can adjust the transformation ratio of the on-load tap changer along with movement of the rack.