The invention discloses a low-voltage circuit regulation and compensation device and a compensation method thereof. The low-voltage circuit regulation and compensation device comprises a compensationcircuit, wherein the compensation circuit comprises a contactor, a transformer, a control sampling circuit, a contactor group, an external bypass switch module and a capacitor module; the compensationcircuit is arranged between a null line and a live line; a voltage input port in the live line is connected with one end of the contactor and one end of the contactor group in series; the contactor is connected with the contactor group in parallel; the other end of the contactor is connected with a built-in bypass and a first winding of the transformer in series; the built-in bypass is connectedwith the first winding of the transformer in parallel; the contactor group is connected to a second winding of the transformer in series; the end of the built-in bypass and the end of the transformerare connected to a voltage output port; and the control sampling circuit is connected with the contactor, the contactor group and the transformer in parallel. By adoption of the compensation method, the voltage at the tail end of a rural line and is effectively increased and the utilization rate of the energy is improved.