The utility model relates to a mine applied electric locomotive regeneration bi-directional DC-to-DC current transformer, comprising a main circuit, a detecting and driving circuit and a control circuit; the detecting and driving circuit comprises a power supply control circuit, a voltage sampling circuit, a current sampling circuit, a protection circuit and an insulated gate bipolar transistor (IGBT) driving circuit; the control circuit takes TMS320F28035 as its core and comprises the TMS320F28035, a signal sampling circuit, an auxiliary function module, a keyboard display circuit, and a CAN communication interface. The beneficial effects of the utility model comprise that it can reasonably utilize the energy produced in brake, thus saving energy; at the same time, the current transformer can be free of vehicle mounted brake resistors, making an electric locomotive a light one while still stabilizing voltage in an alternating current power grid; beyond that, air braking can also be reduced, thereby reducing the use of locomotive brake head with the result of the reduction of workload for repair of an electric locomotive.